Analogues of the pancreatic bovine trypsin inhibitor, their production and use.

Introduction and scope of the invention

Aprotinin is a well characterized 58 amino acid basic protein that acts as an inhibitor of proteinases such as trypsin, chymotrypsin, plasmin and kallikrein. It has become a valuable medicine called trasylol^(R), for the treatment of various diseases, such as. B. Hyperfibrinolytic bleeding and shock causing traumatic bleeding.

It has recently been shown that the replacement of the lysine residue in position 15 of the aprotinin molecule with other amino acids leads to valuable proteinase inhibitors with a modified inhibition spectrum compared to aprotinin (H. Tschesche et al (1985), patent application DE-PS 33 39 693 from 15.5. 85). Depending on the amino acid introduced, these modified inhibitors can e.g. B. act as inhibitors on elastases of the pancreas and leukocytes and / or plasma kallikrein. Although aprotinin variants can be obtained by semisynthetic conversion of aprotinin (H. Tschesche et al, DE-OS 33 39 693), the quantities available are relatively small. In addition, this method does not allow a multiple exchange of amino acids in addition to the lysine residue in position 15.

It has therefore been recognized that the use of recombinant DNA and related technologies would be the most appropriate way to produce large amounts of aprotinin homologues with the desired specificity and inhibitory activity.

Those skilled in the art know that DNA encoding proteins with a known amino acid sequence can be made using the DNA sequence of the genome or the cDNA sequence that is complementary to the mRNA. Amino acids can then be exchanged eg by site-specific mutagenesis.

Another way of obtaining a DNA coding for a protein of known primary structure is to choose codons according to the genetic code and to produce a synthetic gene.

Methods for expressing heterologous DNA in a recombinant microorganism and / or in eukaryotic cells are known.

The object of the present invention is to provide pharmaceutically useful polypeptides / proteins with a high degree of specificity together with a high inhibitory effect. The polypeptides mentioned are peptides with the amino acid sequence of aprotinin and variants thereof, which can be produced by recombinant DNA technologies. The term "variants" refers to polypeptides in which one or more of the amino acids of the original aprotinin sequence have been replaced by other, naturally occurring amino acids. Preferred positions for such an exchange are the positions that are in close contact with the target enzyme within the enzyme-inhibitor complex. These are positions 12, 13, 14, 15, 15, 17, 18, 34, 36, 37, 38 and 39. Position 20 is not included in this contact area; however, its basic nature can be important for kallikrein inhibition in some cases.

Accordingly, the present invention relates to peptides which essentially have the sequence of bovine pancreatic trypsin inhibitor (aprotinin, BPTI), one or more of the amino acids in positions 15, 16, 17, 18, 34, 39 and 52 being substituted by any naturally occurring amino acid is exchanged, except<ul id="ul0001" list-style="none"><li>1. Aprotinin with an exchange in position 15 by one of the amino acids Gly, Ala, Val, Leu, Ile, Met, Arg, Thr, Phe, Ser, Trp or Tyr,</li><li>2nd Aprotinin, which in addition to the exchange in position 15 described under 1. has a further exchange in position 52 by one of the amino acids Glu, Leu, Val, Thr or Ser,</li><li>3rd Aprotinin variants as described under 1. and 2. with an additional Met, which precedes the N-terminal amino acid Arg-1, and</li><li>4th Val-15-Ser-16-Ile-17-aprotinin.</li></ul>

Accordingly, peptides are also preferred which comprise: in position 15 the amino acid Leu, Ile, Val, Phe, Tyr, Trp, Met, Ala, Thr, Ser, Gln, Asn, Arg or Lys, in position 16 the amino acid Val, Met, Thr, Ser, Gln, Asn, Gly, Arg or Ala, in position 17 the amino acid Leu, Ile, Val, Phe, Tyr, Trp, Met, Ala, Thr, Ser, Gln, Asn, Gly, His, Lys or Arg, in position 18 the amino acid Leu, Ile, Val, Phe, Met, Thr, Glu or Gly, in position 34 the amino acid Leu, Ile, Val, Phe, Tyr, Trp, Ala or Thr, in position 39 the amino acid Leu, Ile, Val, Phe, Tyr, Trp, Met, Ala, Thr, Ser, Glu, Gln, Asn, Gly, Arg, Lys, Asp or Pro, and in position 52 the amino acid Leu, Ile, Val, Met, Thr, Ser, Glu, Gln, Asp, Lys or Arg.

The invention particularly preferably relates to<ul id="ul0002" list-style="none"><li>1. Peptides that have the amino acid Val, Leu or Ile, in position 17 the amino acid Leu, Ile, Val, Gln, Thr, Met, Trp, Tyr, Phe, Asn or Arg, in position 39 the amino acid Glu, Asp, Asn, Thr, Val, Leu, Ile, Gln or Arg and in Position 52 has the amino acid Thr, Glu or Met,</li><li>2nd Peptides which have the amino acid Val, Leu or Ile, in position 17 the amino acid Leu, Ile, Val, Gln, Thr, Met, Trp, Tyr, Phe, Asn or Arg, in position 39 the amino acid Glu or Arg and in Position 52 has the amino acid Thr, Glu or Met,</li><li>3rd Peptides, which in Position 15 the amino acid Val, Leu or Ile, in position 17 the amino acid Leu, Ile, Val or Arg, in position 39 the amino acid Glu or Arg and in Position 52 has the amino acid Thr, Glu or Met and</li><li>4th Peptides, which in Position 15 the amino acid Val or Leu, in position 17 the amino acid Leu, in position 39 the amino acid Glu or Arg and in Position 52 has the amino acid Thr, Glu or Met.</li></ul>

According to the invention, the following peptides are most preferred: Val-15-Leu-17- Val-15-Leu-17-Glu-52- Val-15-Leu-17-Thr-52- Val-15-Leu-17-Glu-39- Val-15-Leu-17-Glu-39-Glu-52- Val-15-Leu-17-Glu-39-Thr-52- Leu-15-Leu-17- Leu-15-Leu-17-Glu-52- Leu-15-Leu-17-Thr-52- Leu-15-Leu-17-Glu-39- Leu-15-Leu-17-Glu-39-Glu-52- Leu-15-Leu-17-Glu-39-Thr-52-aprotinin.

The invention also relates to positions within the molecule which are important for certain modes of expression of the proteins via recombinant DNA technology, in particular position 52.

The invention further relates to polypeptides / proteins with the sequences given above, which additionally have methionine in position -1 and / or a leader peptide. The term "leader peptide" refers in this application not only to signal sequences which increase the secretion of the expression product, but also to sequences which comprise a signal sequence and a linker sequence which precede the aprotinin or the sequences of the aprotinin variant. In addition, the term “leader sequence” refers to sequences at both ends of the molecule, these ensuring high expression and / or serving for easier cleaning of the molecules.

The present invention also relates to polypeptides / proteins with the above-mentioned sequences, but which are truncated by one or more amino acids at one or both ends of the molecule, the inhibitory action being partially or completely retained.

Homologs (variants) of aprotinin, as specified above, can be used therapeutically for diseases which are due to the presence of excess amounts of proteinases, eg pancreatic elastase (pancreatitis), serum elastase (arteriosclerosis), leukocyte elastase in chronic and acute inflammation with damage of the connective tissue, in the event of damage to the vessel walls, necrotic diseases and degeneration of the lung tissue. The role played by lysosomal enzymes, in particular leukocyte elastase, in inflammatory reactions due to immunological processes, eg rheumatoid arthritis, or as a myocardial depressant factor or in shock syndromes is equally important.

The use of recombinant DNA and related technologies has been found to be the most appropriate way to produce large amounts of aprotinin homologs with the desired specificity and inhibitory activity.

It has also been shown that aprotinin homologues can be obtained by recombinant DNA technology using a construct in which synthetic genes are bound to the lac Z gene (E. Auerswald et al, (1985), patent application GB-8607523) or not -fused (v. Wilcken-Bergmann et al (1986), EMBO J., 5, 3219-3225). In addition, the natural coding region of aprotinin was expressed as a fusion with the signal sequence of the pho A gene (alkaline phosphatase) (B. Marks et al (1986) J. Biol. Chem., 204, 7115-7118).

It is often easier to achieve high expression of a particular small heterologous protein in a bacterial host using gene fusions. This is due to a variety of reasons. Factors that apparently affect the accumulation of heterologous polypeptides in a host cell include the following:<ul id="ul0003" list-style="none"><li>(1) The heterologous polypeptide can be degraded efficiently by host cell proteinases.</li><li>(2) The heterologous polypeptide can have a toxic effect on the cell.</li></ul>

Although a large number of heterologous proteins with molecular weights above 10,000 daltons have been successfully expressed intracellularly in E. coli, relatively few, small, heterologous polypeptides have so far been able to be expressed well, although many attempts have been made to do so.

In order to overcome this problem, fusion polypeptides have often been used. The disadvantages of this method include the following:<ul id="ul0004" list-style="none"><li>(1) The inserted structural sequence must be in the correct reading frame for the AUG start codon of the fusion partner.</li><li>(2) The heterologous polypeptide must be cleaved chemically or enzymatically from the fusion polypeptide. For this reason, the desired protein must not contain any of the cleavage sites. In many cases, this is a serious problem.</li></ul>

However, it is sometimes possible to express small polypeptides using plasmids that contain multiple copies of the gene (v. Wilcken-Bergman et al (1986), EMBO J., 5, 3219-3225).

Another way to overcome this degradation and / or toxicity problem is to express the heterologous protein in a secretion system. Secretion systems from bacteria, yeasts or fungi can be used. In order to achieve secretion, a suitable leader sequence must be attached to the 5'-end of the aprotinin gene or the aprotinin variants in such a way that the corresponding amino acid sequence comprises a splice site for the signal peptidase before the N-terminal end, which leads to this secreting protein splices.

The present invention relates to synthetic DNA sequences which code for aprotinin homologs. It relates in particular to a DNA which is referred to below as the "master gene" and which has the sequence shown in FIG. 3 and / or functional equivalents thereof. The term "functional equivalents" in relation to the application also means derivatives of the above DNA sequence in which in some codons one, two or three of the bases have been replaced by another base, without this having an effect on the one to be incorporated into the protein Has amino acid (degeneracy of the genetic code).

In order to produce variants of the aprotinin molecule, the master gene is modified with the aid of recombinant DNA technologies (eg site-specific mutagenesis) in such a way that the codon for a certain amino acid is replaced by the codon for another amino acid. With the aid of this method, the various DNA sequences which code for the aprotinin homolog (see the above-mentioned aprotinin variants) can be obtained according to the invention.

The codons for such an exchange are the codons for the preferred amino acids as listed on pages 3, 4, 5 and 6. Depending on the expression system used, the DNA of the present invention can also be a DNA which codes for one of the polypeptide variants as listed in Table 1, which has further sequences upstream at the 5 'end.

Another object of the present invention are expression vectors (plasmids) which contain the DNA which codes for the polypeptides. These plasmids are used to transform a host organism. The present invention also relates to organisms transformed in this way. A large number of organisms which are suitable for transformation are known to the person skilled in the art. The type of plasmid mainly depends on the host organism to be used.

The host organism transformed with the plasmid containing the DNA sequences of the present invention is used to make the aprotinin homologues. The manufacturing process involves the following steps:<ul id="ul0005" list-style="none"><li>(1) culturing the host organism under suitable conditions,</li><li>(2) recovering the peptides from the culture and</li><li>(3) Purify the peptides.</li></ul>

The polypeptides can be purified by known methods in protein chemistry, eg precipitation, chromatography and electrophoresis. The above linker peptides can be useful in such purifications because the characteristics of the linker can be used to facilitate cleaning (an example is given by SJ Bruver and HM Sassenfeld (1985), Trends in Biotechnology, 3, 119-122) .

The present invention also relates to pharmaceutical preparations and preparations which comprise the peptides listed above, and the use of these peptides in the manufacture of pharmaceutical preparations. These pharmaceutical preparations are particularly suitable for the indications described above.

In addition to non-toxic, inert, pharmaceutically suitable excipients, the pharmaceutical preparations contain one or more compounds according to the invention; the invention also encompasses methods of making these preparations.

The present invention also encompasses pharmaceutical preparations in unit doses. This means that the preparations are in the form of individual parts, e.g. B. as tablets, coated tablets, capsules, pills, suppositories and ampoules, the content of active ingredient corresponds to a fraction or a multiple of a single dose. The dose units can e.g. B. contain one, two, three or four single doses or a half, a third or a quarter dose or a single dose. A single dose preferably contains the amount of active ingredient which is given in one administration and which usually corresponds to a whole, half, a third or a quarter of a daily dose.

Non-toxic, inert, pharmaceutically suitable auxiliaries are understood to mean solid, semi-solid or liquid diluents, fillers and formulation auxiliaries of all kinds.

The following are preferred pharmaceutical preparations: tablets, coated tablets, capsules, pills, granules, suppositories, solutions, suspensions and emulsions, pastes, ointments, gels, creams, lotions, powders and sprays.

Tablets, coated tablets, capsules, pills and granules can contain the active ingredient or the active ingredients together with customary auxiliaries, such as. B. (a) fillers and extenders, such as starches, lactose, sucrose, glucose, mannitol and silicon dioxide, (b) binders, such as carboxymethyl cellulose, alginates, gelatin and polyvinylpyrrolidone, (c) moisturizing agents, such as glycerol, (d) disintegrants, such as agar Agar, calcium carbonate and sodium carbonate, (e) solution retarders, paraffin and (f) adsorption accelerators, such as quaternary ammonium compounds, (g) wetting agents, such as cetyl alcohol and glycerol monostearate, (h) adsorbents, such as kaolin and bentonite and (i) lubricants, such as talc, calcium and magnesium stearate and solid polyethylene glycols, or mixtures of the substances as listed under (a) to (i).

The tablets, coated tablets, capsules, pills and granules can be provided with conventional coatings and coatings, which may contain opacifying agents; they can also be present in those preparations which release the active ingredient or the active ingredients preferably only in a certain part of the digestive tract, optionally in a delayed manner, examples of suitable materials for embedding being polymer substances and waxes.

The active substance or substances, optionally together with one or more of the above-mentioned carriers, can also be in the form of microcapsules.

Suppositories can contain the usual water-soluble or water-insoluble carriers in addition to the active substance or substances, e.g. B. polyethylene glycols, fats, e.g. B. cocoa fat, and higher esters (z. B. C₁₄ alcohol with C₁₆ fatty acid) or mixtures of these substances.

Ointments, pastes, creams and gels can contain conventional excipients in addition to the active ingredient or ingredients, e.g. B. animal or vegetable fats, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicon dioxide, talc and zinc oxide, or mixtures of these substances.

Powders and sprays can contain conventional carriers in addition to the active ingredient or ingredients, e.g. B. lactose, talc, silicon dioxide, aluminum hydroxide, calcium silicate and polyamide powder, or mixtures of these substances. The sprays can also contain conventional propellants, e.g. B. chlorofluorocarbons.

Solutions and emulsions can contain conventional carriers in addition to the active ingredient or ingredients, such as solvents, solubilizing agents and emulsifying agents, e.g. B. Water, ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils, especially cottonseed oil, peanut oil, corn oil, olive oil, castor oil and sesame oil, glycerin formal, tetrahydrofuryl sorbate, fatty alcohol, fatty acid, sorbate, fatty acid, or mixtures of these substances.

For parenteral administration, the solutions and emulsions can also be in sterile form that is isotonic with the blood.

Suspensions can contain conventional carriers in addition to the active ingredient or ingredients, such as liquid diluents, e.g. B. water, ethyl alcohol or propylene glycol, suspending agents, e.g. B. ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar and tragacanth, or mixtures of these substances.

The formulations mentioned can also contain dyes, preservatives and additives which improve the smell and taste, e.g. B. peppermint oil and eucalyptus oil, and sweeteners such as saccharin.

The therapeutically active compounds should preferably be present in the above-mentioned pharmaceutical preparations in a concentration of approximately 0.1 to 99.5% by weight, preferably approximately 0.5 to 95% by weight, based on the total weight .

The above-mentioned pharmaceutical preparations can also contain other active pharmaceutical ingredients in addition to the compounds according to the invention.

The above-mentioned pharmaceutical preparations are prepared in a conventional manner by known methods, e.g. B. by mixing the active ingredient or ingredients with the carrier (s).

The active substances or the pharmaceutical preparations can be administered locally, orally, parenterally, intraperitoneally and / or rectally, preferably orally or parenterally, such as intravenously or intramuscularly.

In general, it has proven to be advantageous in both human and veterinary medicine to use the active ingredient or active ingredients according to the invention in total amounts of from about 0.5 to about 500, preferably from 5 to 100 mg / kg of body weight To be administered 24 h, if necessary in the form of several single administrations, in order to achieve the desired results. A single administration contains the active substance or the active substances according to the invention preferably in amounts of approx. 1 up to 250, in particular from 3 to 60 mg / kg body weight. However, it may be necessary to deviate from the doses mentioned, in particular depending on the nature and body weight of the individual to be treated, the nature and severity of the disease, the type of preparation and the mode of administration of the medicine, and the time or the Time period over which the administration takes place.

Thus, in some cases it may be sufficient to administer less than the above-mentioned amount of active ingredient, while in other cases the above-mentioned amount of active ingredient must be exceeded. The specially required optimal dose and the type of administration of the active ingredients can be determined by the person skilled in the art on the basis of his specialist knowledge.

Synthetic genes

The strategy for the synthesis of genes encoding aprotinin and aprotinin homologue is described below:

The known protein sequence of aprotinin and its homologues and the genetic code served to determine the DNA sequence which codes for these polypeptides. All possible base substitutions (degeneracy of the genetic code) as well as all potential restriction sites were considered for the construction of the synthetic DNA sequence. The resulting basic construction for a synthetic aprotinin gene and its homologue is shown in Fig. 1, 2 and 3. The synthetic master gene consists of four blocks (labeled alpha, beta, gamma, delta), each of which has restriction endonuclease recognition sites at both ends (see also Example 3, FIG. 1). This allows a simple modification and modification of the DNA sequences (codon use, mutations, amplification of genes, protein engineering) for e.g. B. unfused expression or expression as fusion proteins. Fusion proteins are constructed so that the desired protein can be released from the fusion by enzymatic or chemical methods or is released into the periplasmic space during secretion.

The entire spectrum of protein construction technology is possible with this construction. Amplification of the gene can be achieved by adding suitable linker sequences. An exchange of amino acids is possible in all positions, except for those that are part of a recognition site for a restriction endonuclease. These (and all others) can be z. B. be changed by site-specific mutagenesis. The plasmid selected for cloning the synthetic genes was pUC 8 (J. Vieira and J. Messing (1982), Gene, 19, 259). The plasmid is commercially available from PL Biochemicals. The synthetic genes were cloned into pUC 8 and sequenced directly using the super-coil DNA sequencing method (literature by KJ Chen and PH Seeburg (1985), DNA, 4, 165-170).

Expression plasmids

For the expression of aprotinin homologues as fusion proteins, plasmids were used in which the corresponding gene at (1) the 3'-end of the coding region of the lac Z gene (beta-galactosidase) (U. Rüther and B. Müller-Hill (1983), EMBO J., 2, 1791-1794) or to (2) the codon of amino acid 98 of the polymerase of phage MS-2 (E. Remault et al (1981), Gene, 15, 81-93).

For the expression of aprotinin homologues which were secreted into the periplasmic space or into the medium, the respective gene was cloned into an alpha-amylase secretion vector (MA Sullivan et al (1984), Gene, 29, 21-26). The gene was modified by introducing an XbaI cleavage site at the 5'-end of the block alpha. Such a construction enables the primary translation product to be split off during secretion by the endogenous leader peptidase to form the desired aprotinin or the aprotinin variant.

The insertion of the synthetic genes of aprotinin and aprotinin variants into the correct cloning sites and in the correct reading frame leads in all cases to the desired fusion proteins.

E. coli strain RRI ΔM15 was transformed with one of the following three expression plasmids pES 44.1.1, pES 45.1.3 or pCH 2742 and on June 26, 1987 in the German Collection of Microorganisms, D-3400 Göttingen, Grisebachstr. 8 / FRG deposited under the specified deposit number: E. coli RRI Δ M15 pES 44.1.1 DSM 4157 E. coli RRI Δ M15 pES 45.1.3 DSM 4158 E. coli RRI Δ M15 pCH 2742 DSM 4159

Effectiveness of the aprotinin variants

By changing the amino acid sequence of aprotinin in the positions given in Table 1 it was surprisingly found that not only the inhibitory activity against human leukocyte elastase could be increased significantly, but also variants were found which potent inhibitors of other serine proteases, such as human cathepsin G or human pancreatic elastase I.

Examples of aprotinin variants which show an increased inhibitory action against human leukocyte elastase are those which have the amino acid leucine in position 17. These gave a K_i-Value that is almost an order of magnitude better than variants that have the original amino acid arginine in position 17. The improvement in efficacy of these inhibitors was also demonstrated in more relevant test models, eg in a degradation assay using subendothelial matrix or in a model of acute pulmonary inflammation in hamsters.

Examples of aprotinin variants which, in addition to human leukocyte elastase, inhibit other important leukocyte proteases, such as cathepsin G, are variants which have the amino acid leucine in positions 15 and 17.

Examples of aprotinin variants which inhibit human pancreatic elastase I are those which have the amino acid glutamate in position 39 and leucine in position 17.

Materials and methods

The synthetic genes, recombinant plasmids and expression vectors which contain the synthetic genes can be produced and characterized using the following materials and methods:

materials

1) enzymes

DNA polymerase, (Klenow); T4 DNA ligase (0.9 units / µl); Lysozyme, RNase A and polynucleotide kinase from Boehringer, Mannheim. Restriction enzymes from Boehringer, Mannheim, Bethesda Research Labs and Biolabs were used according to the manufacturer's instructions.

2) reagents

ATP, dATP, TTP from Sigma; DTE, thymidine from Serva, Heidelberg; Sucrose from Bethesda Research Labs; Diaminopimelic acid, rubidium chloride from Sigma; all other reagents were pro analysi (Merck, Darmstadt and / or Sigma).

3) DNA / plasmids

Plasmid pUC 8; 5′-phosphorylated Bam H1 linker from PL Biochemicals (Pharmacia); Plasmid pUR 278 (U. Rüther and B. Müller-Hill (1983), EMBO J., 2, 1791-1974); Plasmid pPLc24 obtained from W. Fiers, University of Ghent, Belgium (construct of pPLc24: Remault et al, Gene 15, 81-93 (1981).

4) tribes

E. Coli RR1 Δ M15 from ATCC (No. 35 102) E. coli C 600 [pcI 857] obtained from W. Fiers, University of Ghent, Belgium (construct of pcI 857: Remault et al, Gene 22: 103-113 (1983); E. coli C600: ATCC 23724). Bacillus subtilis from DSM (No. 704).

5) media

Bacto tryptone; Bacto yeast extract; Bacto agar from DIFCO LB medium (for 1 l): 10 g bacto-tryptone, 5 g bacto-yeast extract, 10 g NaCl, adjusted to pH 7.5 with NaOH. kappa 1776 medium (for 1 l): 25 g bacto-tryptone, 7.5 g bacto-yeast extract, 20 ml 1M tris-HCl pH 7.5, dissolved in 950 ml distilled water and treated in an autoclave. After cooling, the following were added: 5 ml of 1M magnesium chloride, 10 ml of 1% diaminopimelic acid, 10 ml of 0.4% thymidine, 25 ml of 20% glucose (all of the added solutions were sterilized by filtration). Agar plates were made by adding 15 g of Bacto agar to 1 liter of the appropriate medium.

6) antibiotics

Chloramphenicol and Kanamycin sulfate from Boehringer, Mannheim. Ampicillin and tetracycline from Serva, Heidelberg.

7) Buffers and Solutions

10th mM ATP in water 10X ligase mix: 0.5 M Tris-HCl (pH 7.4); 0.1 M MgCl₂; 0.1 M DTE; 10 mM ATP 10X SP-50: 100mM Tris-HCl (pH 7.5); 100 mM MgCl₂; 500 mM NaCl; 10mM DTT 10X SP-100: 100mM Tris-HCl (pH 7.5); 100 mM MgCl₂; 1 M NaCl; 10mM DTT 10X SP-O: 100mM Tris-HCl (pH 7.5); 100 mM MgCl₂; 10mM DTT 20X E buffer: 0.8 M Tris; 0.4 M sodium acetate; 40 mM EDTA, pH 8.3

Transformation buffer (prepared as follows): 15 g sucrose, 1 ml 3.5 M KOH, 1 ml 1 M CaCl₂, 2 ml 5.0 M RbCl, are bidistilled with aqua. brought to 50 ml, adjusted to pH 6.2 with 10% acetic acid, 1 ml 4.5 M MnCl₂ is added, adjusted to pH 5.8 with 10% acetic acid, with double-distilled water. brought to 100 ml and sterile filtered. TE buffer: 10mM Tris-HCl pH 8.0, 0.1mM EDTA 10X NT buffer: 0.5 M Tris-HCl pH 7.2; 0.17 MgSO₄, 1 mM DTE Lysozyme mix: 50 mM glucose, 2 mg / ml in 1 mM EDTA, 10 mM Tris-HCl pH 8.0, freshly prepared before use Phenol / Sevag: mixture of 1 volume of 80% phenol and 1 volume of Sevag (chloroform: iso-amyl alcohol, 24: 1) TEABC buffer: 1 M triethylamine in distilled water, pH adjusted to 7.5 with gaseous CO₂ 10X PNK mix: 0.5 Tris-HCl (pH 7.6), 0.1 M MgCl₂, 50 mM DTE, 1 mM EDTA 10X ligase mix: 0.5 M Tris-HCl (pH 7.4), 0.1 M MgCl₂, 0.1 M DTE, 10 mM ATP

Methods

Standard recombinant DNA technology methods were used, as described in Maniatis et al (1982), Molecular Cloning Cold Spring Harbor Laboratory, Cold Spring Harbor, USA:

Standard ethanol precipitation

DNA pellets were dissolved or solutions were adjusted to 0.3 M sodium acetate, 2 volumes of ethanol were added, incubated for 15 min at -70 ° C. and centrifuged. The pellets were washed twice with 80% ethanol and dried in vacuo.

Standard phenol extraction

The solutions were mixed thoroughly with Phenol / Sevag (1: 1), centrifuged and the phenol phase re-extracted with 1/10 volume of TE buffer or water. The aqueous phases were combined.

Standard dephosphorylation of DNA

Completely degraded and purified DNA was dissolved in water and adjusted to 1X CIP buffer (standard total volume 48 µl). The reaction was started at 37 ° C. by adding 1 μl (20 units) phosphatase from calf intestine (CIP); after 30 min, 1 μl of CIP was again added. The reaction was stopped after 1 h by adding 5 μl of 50 mM EGTA and incubated at 65 ° C. for 10 min. For the dephosphorylation of DNA with blunt ends or staggered 5'-ends, incubations were carried out repeatedly for 15 min at 37 ° C and 15 min at 56 ° C. The DNA was extracted with phenol / Sevag and ethanol precipitated.

Standard ligation

A five-fold molar excess of the fragment over the vector was used for standard ligations. The final concentration of the DNA was 25 µg / ml. The DNA was dissolved in a small amount of TE buffer. The ligation was carried out with T4 DNA ligase in a 1X ligase mix (50 mM Tris-HCl pH 7.4, 10 mM MgCl₂, 10 mM DTE, 1 mM ATP) in a standard volume of 30 μl for 16 h at 14 ° C.

Standard restriction endonuclease cleavage

Restrictions with restriction endonucleases were mainly carried out according to the manufacturer's instructions.

Purified, salt-free DNA was dissolved in buffer (SP-O, SP-50 or SP-100, depending on the enzyme used) and cleaved with a suitable amount of enzyme. The material was then extracted with phenol and precipitated with ethanol.

Standard isolation of DNA fragments after agarose gel electrophoresis

The DNA fragments were separated by agarose gel electrophoresis (see T. Maniatis et al, 1982, Cold Spring Harbor Laboratory, Molecular Cloning), stained with ethidium bromide and cut out under long-wave UV light. The cut-out parts were placed in a dialysis tube, filled with 0.5X E buffer (volume ratio buffer: gel slices 1.5: 1); the gel sections must be well surrounded by buffers. The sealed, bubble-free tube was placed in an electrophoresis chamber filled with 0.5X E buffer. Electrophoresis was carried out at 200 V for 30 minutes, then the current was reversed for 30 seconds to release the DNA from the wall of the dialysis tube. The buffer surrounding the gel slices was carefully removed and the DNA was purified on DEAE cellulose or DE 52 columns (see above).

Standard transformation process

Transformations were carried out according to the method of D. Hanahan (1983), J. Mol. Biol., 166, 557-580).

1 ml of a 20 ml overnight culture of the host strain, inoculated with a single colony and grown in kappa 1776 medium (37 ° C, shaker at 200 rpm) was used to inoculate 100 ml of prewarmed (37 ° C) kappa 1776 medium.

This culture was grown under the same conditions. Cell growth was stopped at 0.2 OD (500 nm). After cooling to 4 ° C. and centrifuging, the cell pellet was resuspended in 20 ml of ice-cold transformation buffer and incubated for 5 minutes at 0 ° C. The suspension was centrifuged again (3000 rpm, 4 ° C., 15 min) and the pellet was resuspended in 4 ml of ice-cold transformation buffer. After adding 7 μl DMSO to 200 ml aliquots, the cells were incubated in ice water for 15 to 60 min. To such an aliquot of complete cells, DNA, dissolved in 20 μl TE buffer, was added and the mixture was incubated in ice water for 20 min and then at 42 ° C. for 3 min. 1 ml prewarmed (37 ° C) kappa 1776 medium was then inoculated with such an aliquot and cultured at 37 ° C for 1 h. To spread the transformants, the cells were centrifuged (3000 rpm, 15 min, 4 ° C.), resuspended in YT medium and spread on indicator plates. Depending on the number of transformants to be expected, an appropriate amount of the suspension was used for spreading.

Fast analytical standard plasmid isolation

The method described represents a modification of the method by HC Birnboim and J. Doly (1979), Nucleic Acids Res. 7, 1513; T. Maniatis et al (1982), Cold Spring Harbor Laboratory, Molecular Cloning. A 2 ml overnight culture was prepared for each transformant to be analyzed (37 ° C., 16 h, rotary wheel). 1.5 ml of the culture was centrifuged at 12,000 xg for 1 min. The pellet was dissolved in freshly prepared lysozyme mix solution and incubated for 5 min at 20 ° C.

The sample was incubated for a further 5 min on ice after the addition of freshly prepared ice-cold 0.2 M NaOH, which contains 1% SDS. 150 μl of ice-cold potassium acetate, pH 4.8, were added to precipitate the chromosomal DNA and the proteins. After incubation on ice for 5 minutes and centrifugation at 12,000 xg for 10 minutes, the supernatant was transferred to a fresh test tube and extracted with Sevag. 500 ul isopropanol was added to the aqueous phase. The mixture was then incubated at -20 ° C for 30 min. After centrifugation (10 min, 12,000 xg), the pellet was washed with 80% ethanol and briefly dried in vacuo.

Standard DNA sequencing

Standard DNA sequencing was performed as described in the manufacturer's protocol (guidelines for quick and easy plasmid sequencing, Boehringer Mannheim (1986)).

Growth and induction of bacterial strains

Bacterial cultures were grown in media supplemented with suitable antibiotics. To achieve the expression of β-galactosidase fusion proteins, E. coli RRI M15, transformed with the expression plasmid pES 44.1.1 or pES 45.1.3, was inoculated in 2 ml LB-ampicillin medium. After 12 to 14 hours of growth at 37 ° C in shake flasks, 1 ml samples were used directly to inoculate 100 ml LB ampicillin medium containing 0.2 mmol IPTG. A clone containing pUR 278 without aprotinin gene insert was cultured as a negative control under the same conditions. After growing for 12 to 16 hours at 37 ° C with shaking, the cells were harvested by centrifugation at 5,000 rpm (10 min) in a Beckman JA 10 rotor.

Standard SDS polyacrylamide gel electrophoresis

The proteins were detected using SDS-polyacrylamide electrophoresis according to Laemmli, (1970), Nature, 277, p. 680 (see also BD Hames and D. Rickwood, 1981, Gel Electrophoresis of Proteins, IRL Press Limited, Oxford).

Approx. 1 x 10⁹ cells were centrifuged, dissolved in SDS sample buffer (70 mM Tris, 10% glycerol, 1% SDS, 5% beta-mercaptoethanol, 0.1 mM EDTA), incubated for 5 min at 95 ° C and on each lane given up. After electrophoresis, the gels were stained with Coomassie blue R 250.

Determination of the amino acid sequence

Approx. 0.5 to 2 nmoles of the protein were dissolved in 30 ul TFA. The sample was placed on a glass fiber filter which had been pretreated with 3 mg polybrene. The sequence analysis was carried out using the gas phase protein sequencer from Applied Biosystems (Inc. USA) according to Hewick (RM Hewick, MW Hunkapiller, LE Hood, W. Dreger 1981, J. Biol. Chem. 256, 7990-7997). The amino acid phenylthiohydantoin derivatives released in each step were analyzed using a cyano-HPLC column (DuPont) and a separation system as described by Beyreuther (K. Beyreuther, B. Biesler, J. Bowens, R. Dildrop, K. Neufer, K. Stüber, S. Zais, R. Ehring, P. Zabel (1983), Modern Methods in Protein Chemistry, 303-325, Walter de Gruyter + Co., Berlin). A Waters HPLC system with an M 510 pump, a WISP 710B auto-injector, an M 481 LC spectrophotometer and a Shimadzu integrator C-R3A was used.

Acid hydrolysis and amino acid analysis

Approx. 1 nmol of the protein was placed in a Pyrex test tube, to which 200 ul 6M HCl (constant boiling HCl) containing 0.05% 2-mercaptoethanol (IT Potts Jr. 1969, Anal. Biochem. 131, 1-15) , were added. The test tubes were sealed under vacuum and incubated at 110 ° C for 22 h. The hydrolyzates were quickly dried, dissolved in 150 ul 0.2 M sodium citrate buffer pH 2.2 and filtered. The amino acid analysis was carried out using a Biotronic LC 5000 amino acid analyzer equipped with a fluorescence detector and a Shimadzu C-R2AX integrator. The amino acids were quantified after reaction with o-phthalodialdehyde, essentially as described by Benson (JR Benson, PE Hare 1975, Proc. Natl. Acd. Sci. USA 72, 619-622).

Inhibition assays for leukocyte elastase

Leukocyte elastase was determined as described by K. Nakajima et al (1979), J. Biol. Chem. 254, 4027. The determinations were carried out under the following conditions:<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="2" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="78.75mm" /><colspec colnum="2" colname="col2" colwidth="78.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Substrate (stock solution)</entry><entry namest="col2" nameend="col2" align="left">0.1 M methoxysuccinyl-L-alanyl-L-alanyl-L-prolyl-L-valine-p-nitro-anilide in dimethylformamide. The stock solution was stored at -18 ° C.</entry></row><row><entry namest="col1" nameend="col1" align="left">Substrate (amount per test)</entry><entry namest="col2" nameend="col2" align="left">6.5 µl</entry></row><row><entry namest="col1" nameend="col1" align="left">Substrate manufacturer</entry><entry namest="col2" nameend="col2" align="left">Bachem Bubendorf / Switzerland</entry></row><row><entry namest="col1" nameend="col1" align="left">Enzyme (stock solution)</entry><entry namest="col2" nameend="col2" align="left">0.01 mg / ml human leukocyte elastase in 50% ethylene glycol. The solution was stored at -18 ° C.</entry></row><row><entry namest="col1" nameend="col1" align="left">Enzyme (amount per test)</entry><entry namest="col2" nameend="col2" align="left">5 µl</entry></row><row><entry namest="col1" nameend="col1" align="left">Enzyme manufacturer</entry><entry namest="col2" nameend="col2" align="left">Elastin Products Company Pacific / USA</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">buffer</entry><entry namest="col2" nameend="col2" align="left">0.2 M Tris / HCl, pH 8.0 + 0.05% Tween 80</entry></row></tbody></tgroup></table></tables>

General procedure

The inhibitor sample was diluted with an amount of buffer so that the final volume (after adding the substrate) was 0.65 ml. The enzyme was then added and the mixture was left at room temperature for 30 minutes. Finally, the substrate solution was added and the increase in absorbance at 405 nm was then automatically recorded for each sample. The linear increase in absorbance during the first 10 min (Δ OD) was taken as a measure of the enzyme activity.

To determine the inhibitory effect, the enzyme activity was measured with and without the addition of inhibitors. The percentage of inhibition was calculated as follows:<maths id="math0001" num=""><img file="EP0307592A2_D0001.tif" /></maths>

Determination of K

<u style="single">i</u>

-Values ​​from the titration curves of human leukocyte elastase with the inhibitors

Various amounts of inhibitor were added to a series of solutions containing about 200 ng of human leukocyte elastase in 900 μl of 0.2 M Tris buffer pH 8.0, each with 0.05% Tween 80. The mixtures were kept at room temperature at least 2 hours after the volume had been made up to 985 μl with test buffer. Then 15 µl of a mixture consisting of 10 µl substrate stock solution - 59 mg MeOSuc-Ala-Ala-Pro-Val-pNA per 1 ml dimethyl sulfoxide - and 990 µl test buffer after 5 minutes equilibration at 30 ° C in one thermostatted cuvette holder was added to each sample and the increase in absorbance at 405 nm was determined. The K_iValues ​​were calculated according to MW Empie and M. Laskowski jr., Biochemistry 21, 2274-2284 (1982) using the following equation:<maths id="math0002" num=""><img file="EP0307592A2_D0002.tif" /></maths>

In this equation [E_f] and [I_f] represents the molar concentrations of non-complexed enzyme and non-complexed inhibitor; [EI] is the molar concentration of the enzyme-inhibitor complex.

Examples

example 1

Synthesis and purification of DNA fragments coding for Val-15 aprotinin variants

The oligonucleotides comprising the gene (see Figure 2) were made using solid phase synthesis methods. The synthesis scheme for the oligomers provides for the use of proton-activated, protected 2'-deoxyribonucleotide phosphoramidites. All sequencing steps were carried out in an automated manner on an Applied Biosystems Model 380 DNA synthesizer using protected nucleotides, solvents, chemicals and reagents obtained from the manufacturer. The solid phase support, from the same manufacturer, was controlled pore glass to which the starting 3′-nucleotide already adhered. Certain modifications have been introduced in the automated response cycle in accordance with the manufacturer's process instructions and user bulletins. After completion of the synthesis, the oligomers were unblocked and cleaved from the solid support in the DNA synthesizer according to the manufacturer's instructions.

The blocking groups were further removed by heating the aqueous solution containing the oligomer with concentrated ammonium hydroxide for 4 to 24 hours at 55 ° C. in a sealed vial. The solution obtained was evaporated, the residue was dissolved in 0.01 M triethylammonium bicarbonate buffer, pH 7.0 (TEAB buffer). This solution was made using Sephadex-G 50^(R)Gel filtration resin chromatographed. This column was prepared in the same TEAB buffer and eluted with it. The material eluting with the empty volume was combined and the solution was evaporated.

A portion of the residue (10 to 40% of the absorbance units at 260 nm), dissolved in a feed buffer (composition: 0.1% bromophenol blue, 0.1% xylene cyanol, 10 mmol disodium EDTA, in formamide) was electrophoresed on polyacrylamide gels further cleaned. The gel size was 18 x 32 cm with a thickness of 1.5 mm. The well for each oligomer purified in this way was 2 to 5 cm wide; up to 5 oligomers were purified on a single gel. The concentration of the acrylamide in the gel varied from 14 to 20% depending on the chain length of the desired product. A 14% acrylamide gel is preferred for longer oligomers, while shorter oligomers have been purified on up to 20% acrylamide gel. The gels also contained 7 M urea and Tris-borate-EDTA buffer (0.1 M Tris, 0.1 M borate, 0.2 mM EDTA, pH 8.3). The running buffer was the same Tris-Borate-EDTA mixture. Electrophoresis was carried out at 20 to 60 watts, constant current, for 18 to 6 hours. Such standardized methods are described in various "User Information Bulletins" available from Applied Biosystems.

After electrophoresis is complete, the gel is placed in a plastic wrap and the oligomers are visualized by exposure to ultraviolet light. This visualization is done by placing the packaged gel on a plate for fluorescent thin layer chromatography and viewing the gel with a short-wave UV light source. Using this visualization process, the desired product appears as the slowest migrating, mostly blue, DNA fragment. The desired band is cut out of the gel. The DNA oligomer is made from the gel slices on powdered diethylaminoethyl (DEAE) cellulose using an EpiGene D gel^(R)-Electrophoresis apparatus eluted. The oligomer is obtained from the cellulose by elution with 1 M TEAB buffer. The buffer solution containing the oligomer is evaporated, the residue is dissolved in 0.01 M TEAB buffer and then desalted by passing over a Sephadex-G 50 described above^(R)Column is directed. The material eluting in the empty volume is combined and lyophilized to obtain the end product.

Using the methods described above, about 0.5 to 5.0 A₂₆₀ units of each of the purified oligomers were obtained.

Example 2

Construction of a synthetic master gene for Val-15-Glu-52-aprotinin and insertion into plasmid pUC8 to obtain plasmid pRK 54.1.1

The construct of the master gene is shown in Fig. 1. It is composed of the building blocks alpha, beta, gamma and delta and is obtained by assembling the 15 purified oligonucleotides shown in FIG. 2. The DNA sequence shown in Fig. 3 comprises the initiation codon ATG, two termination codons, TAG and TAA, the terminal restriction site Eco RI, Hind III and Bam HI and internal restriction sites. The choice of these sites facilitated the cloning of the coding sequence and its modification.

In addition to the fragments, the construction used to produce this synthetic gene also requires the use of polynucleotide kinase, T4 DNA ligase and restriction enzymes, as described in detail under materials and methods.

Fifteen purified oligonucleotide fragments were dissolved in 50 mM TEABC (triethylammonium bicarbonate buffer, pH 7.5) with a final concentration of 10 pmol / µl. The phosphorylation of all fragments was carried out in four separate parts (questions 1, 3; questions 2, 4, 6; questions 5, 7, 9, 11, 13; questions 8, 10, 12, 14, 16). For preparative purposes, 80 pmoles of each fragment were dissolved in a mixture of 1X PNK-MIX, 2 µM ATP, 0.5 µCi 32 gammaATp per 10 pmole fragment, 10 units PNK per pmole fragment, so that the following total volumes were obtained: For questions 1, 3: 300 µl; for questions 2, 4, 6: 400 µl for Frag. 5, 7, 9, 11, 13; and frag. 8, 10, 12, 14, 16: 700 µl. Each partial sequence was implemented at 37 ° C. for 30 min. All partial sequences were phenolized, precipitated with ethanol, washed and dried.

For hybridization purposes, Frag. 1, 3 and frag. 2, 4, 6 (Block A) dissolved and mixed in 1X Ligase Mix with a total volume of 120 µl, incubated for 5 min at 70 ° C, cooled to room temperature within 5 h. The other fragments (Block B) were hybridized in 240 ul using the same procedure.

For ligation purposes, the solution from block A was supplemented with 12 ul 10 mM ATP, 12 ul 100 mM DTE, 20 ul T4 DNA ligase; the solution of block B was supplemented twice. The reaction took place at 14 ° C. for 7 h. After 10 μl of T4 DNA ligase had been added to block A and 20 μl had been added to block B, the mixture was incubated again at 14 ° C. for 45 min. These mixtures were phenolized, ethanol precipitated and dried.

The block A obtained was dissolved in 90 ul 1X SP-100 and 10 ul Eco RI (10 U / ul), block B in 90 ul 1X SP-50 and 10 ul Bam HI and incubated at 37 ° C for 1 h. The reactions were stopped by phenol extraction and ethanol precipitation; gel electrophoresis was performed on a 6% polyacrylamide gel and the DNA blocks were obtained by the same method as described in Example 1.

Equal amounts of radio-labeled blocks A and B were dissolved in water, adjusted to 1X ligase mix and - as described above - hybridized to a synthetic gene for final ligation. For this purpose, 3 ul 10 mM ATP, 3 ul 100 mM DTE, 3 ul T4 DNA ligase to 22 ul hybridization mixture were added and incubated at 14 ° C for 7 h. Another 1 μl of T4 DNA ligase was added and the reaction was continued at 14 ° C. for 45 min. The ligation product was purified by phenol extraction and ethanol precipitation. A standard restriction enzyme cleavage (Bam HI 1.5 ul, Eco RI 1.5 ul double cleavage) was carried out in SP-50. The material was extracted with phenol; before the ethanol precipitation, the aqueous solution was adjusted to 3 mM MgCl₂, 0.3 M sodium acetate. Then electrophoresis was carried out on 6% polyacrylamide gel and the gene was obtained by the same procedure as described in Example 1.

The synthetic Val-15-Glu-52-aprotinin master gene obtained by this method was inserted into an EcoRI / Bam HI digested pUC8 vector (J. Vieira and J. Messing, Gene 19 259 (1982)) as inserted as follows:

Purified pUC8 DNA (ca. 30 pmol) was digested twice with EcoRI and Bam HI under standard restriction endonuclease cleavage conditions, whereby a small internal EcoRI-Bam Hi fragment was cleaved out. This preparation was dephosphorylated with calf intestine phosphatase, separated by agarose gel electrophoresis; the large EcoRI-Bam Hi fragment of the vector was purified (standard conditions).

PRK 54.1.1 (see FIG. 4) was constructed by ligating the total amount of purified synthetic aprotinin gene with 1 pmole vector (1.8 units T4 DNA ligase, 1X ligase mix, total volume 45 μl, 7-hour incubation at 14 ° C, addition of 1 unit of T4 DNA ligase and 45-minute reincubation at 14 ° C).

Using the transformation method according to D. Hanahan, E. coli strain RRI delta M15 (A. Kalnins et al (1983), EMBO Journal 2, 593, ATCC 35102) was used as the host cell. 15 "white" transformants were obtained on indicator plates which contained 200 μg / ml ampicillin. All 15 transformants were screened using a modification of the Birnboim and Doly 1979 rapid plasmid isolation method. For this purpose, pellets of the 15 samples were redissolved in 30 μl of 1X SP-100, which contains 1 μg of RNase A. Restriction cleavage was carried out with Eco RI and Bam HI.

After gel electrophoresis, it was found that four of the fifteen transformants contained plasmid DNA which had an approximately 200 base pair Eco RI-Bam HI fragment. All transformants containing this Eco RI-Bam HI fragment were grown on a large scale and the plasmids of each isolated and further analyzed. Two of them were sequenced according to the standard sequencing procedure as described in materials and methods; all had the sequence of the Val-15-Glu-52 aprotinin gene.

Example 3

Recombinant plasmids pNH 02.1.1. (Val-15-Leu-17-Glu-52-aprotinin), pNH 16.1.1. (Val-15-Leu-17-Glu-39-Glu-52-aprotinin), pRK 126.1.24 (Val-15-Leu-17-aprotinin) and pRK 113.1.1. (Val-15-Leu-17-Thr-52-aprotinin)

The recombinant plasmid pNH 02.1.1. (Fig. 5) contains a coding region for the synthetic Val-15-Leu-17-Glu-52-aprotinin gene. The recombinant plasmid pNH 16.1.1. (Fig. 6) contains a coding region for the synthetic Val-15-Leu-17-Glu-39-Glu-52-aprotinin gene.

The plasmid pNH 02.1.1. (Val-15-Leu-l7-Glu-52-aprotinin) was obtained by exchanging a beta block which represents an Apa I - Stu I fragment and a codon for Leu in position 17 instead of Arg (see FIG. 7) contains.

Approx. 100 pmol of the synthetic ss DNA fragments beta-EA10A and beta-EA10B (FIG. 7) were dissolved in 20 μl of water, warmed to 95 ° C. for 5 min and slowly (5 h) cooled to room temperature. The hybridized, unphosphorylated fragment was ligated with 1.5 pmol of purified DNA from pRK 54.1.1, which lacked the Apa I - Stu I fragment.

E.coli RRIΔM15 was transformed with 50% of the ligation mixture. Of 1,500 transformants, 24 were tested by analytical plasmid isolation and restriction analysis.

All were positive; two of them were sequenced as described in Materials and Methods. The transformant pNH 02.1.1. was used for the further experiments.

The plasmid pNH 16.1.1, which contained the Val-15-Leu-17-Glu-39-Glu-52-aprotinin gene, was obtained by simply exchanging a gamma block which contains a Stu I - Sst II fragment of pNH 02.1. 1 and contains a codon for Glu in position 39 instead of Arg.

Approx. 100 pmol of the synthetic ss DNA fragments gamma-EA 2A and gamma-EA 2B (FIG. 7) were dissolved in 20 μl of water, heated to 95 ° C. for 5 min and slowly (5 h) cooled to room temperature. The hybridized and unphosphorylated fragment was ligated with 1.5 pmol of purified DNA from pNH 02.1.1, which lacked the Stu I - Sst II fragment.

E.coli RRI Δ M15 was transformed with 50% of the ligation mixture. The E. coli transformants were tested by analytical plasmid isolation and restriction analysis. A positive clone was sequenced as described in materials and methods. The transformant pNH 16.1.1 was used for the further experiments.

The plasmid pRK 126.1.24 (Val-15-Leu-17-Met-52-aprotinin) was obtained from pNH 02.1.1 by exchanging a delta block containing the codon for threonine in position 52 instead of Glu. Approx. 100 pmol of the synthetic ss DNA fragments delta-EA 1A and delta-EA 1B (FIG. 7) were dissolved in 20 μl of water, heated to 95 ° C. for 5 min and slowly (5 h) cooled to room temperature. The hybridized, unphosphorylated fragment was ligated with 1.5 pmol of purified DNA from pNH 02.1.1, which lacked the Sst II - Bam HI fragment.

E.coli RRI M15 was transformed with 50% of the ligation mixture. The E.coli transformants were tested using analytical plasmid isolation and restriction analysis. A positive clone was sequenced as described in materials and methods. The transformant pRK 126.1.24 was used for the further experiments.

The plasmid pRK 113.1.1 (Val-15-Leu-17-Thr-52-aprotinin) was obtained from pNH 02.1.1 by exchanging a delta block which contained the codon for threonine in position 52 instead of glutamic acid. Approx. 100 pmol of the synthetic SS DNA fragments delta-EA7A and delta-EA7B (FIG. 7) were dissolved in 20 μl of water, heated to 95 ° C. for 5 min and slowly (5 h) cooled to room temperature. The hybridized, unphosphorylated fragment was ligated with 1.5 pmol of purified DNA from pNH 02.1.1, which lacked the SstII / Bam Hi fragment. E.coli RRIΔM15 was transformed with 50% of the ligation mixture. The E.coli transformants were tested by analytical plasmid isolation and restriction analysis. A positive clone was sequenced as described in materials and methods. The transformant pRK 113.1.1 was used for the further experiments.

Example 4

Expression plasmids pES 044.1.1, pES 045.1.3, pNH 05.1.1 and pNH 21.1.1

An example of the expression of the genes of aprotinin variants in E. coli is given below, specifically by expression of the genes mentioned as fusions with the lacZ gene (U. Rüther and B. Müller-Hill (1983), EMBO Journal, 2, 1791-1794) or with the N-terminal part of RNA polymerase from phage MS-2 (Remault et al (1981), Gene 15, 81-93).

The aprotineines obtained from the plasmids pNH 02.1.1 (Val-15-Leu-17-Glu-52-aprotinin) and pNH 16.1.1 (Val-15-Leu-17-Glu-39-Glu-52-aprotinin) were obtained ligated into the expression plasmid pUR 278 (U. Rüther and B. Müller-Hill (1983), EMBO Journal, 2, 1791-1794).

The Bam HI and Hind III cloning sites were selected for cloning the synthetic aprotinin in the expression vector pUR 278. For this reason, it was necessary to modify the aprotinin gene by adding a Bam HI site at the 5'-EcoRI end of the gene and using the Hind III site at the 3'-end (see Fig. 8).

5 pMol of the plasmid pNH 02.1.1 were completely cleaved with EcoRI (1.5 pmol / µl) in 50 µl 1X SP-100 for 5 h at 37 ° C.

After cleavage, the material was extracted with phenol, precipitated with ethanol and dried under vacuum.

The protruding 5'-EcoRI ends of this material were filled in enzymatically with DNA polymerase I (Klenow fragment), dATP and TTP.

5 pmoles of this DNA were dissolved in 2 ul 10 mM dATP, 2 ul 10 mM TTP, 5 ul 10 x NT buffer and 39 ul water. Then 2 ul DNA polymerase I (Klenow fragment, 5 units / ul) were added and incubation (30 min) was carried out at room temperature.

The material was extracted with phenol, precipitated with ethanol, washed twice with 80% ethanol and dissolved in 20 ul TE buffer. 20 µl of this material with smooth ends were used for ligation with Bam HI linker. For this purpose, 200 pmol phosphorylated Bam HI linker was ligated to 10 pmol DNA ends (standard ligation conditions, 4.5 ul T4 DNA ligase, total volume 60 ul) and incubated at 14 ° C. for 18 h. The reaction mixture was extracted with phenol / Sevag, precipitated with ethanol, washed, dried and dissolved in 10 μl TE.

To produce the synthetic aprotinin with Bam HI and Hind III termini, the "linker-provided" linear plasmid (10 pmol) was first cleaved with Hind III and then with Bam HI under standard conditions. After separation by 1.8% agarose gel electrophoresis, the fragment was isolated and carefully purified (see standard method).

Vector production

The stock vector pUR 278 (approx. 5 pmol) was first cleaved with Hind III (standard conditions), purified by phenol / Sevag extraction and ethanol precipitation, redissolved and then cleaved with Bam HI (standard conditions). This material was layered on a 1% agarose gel, subjected to electrophoresis, isolated and purified according to standard conditions to free it from the 18 base pair Bam HI - Hind III fragment that would compete with the synthetic aprotinin gene for ligation.

Ligation and transformation

For the ligation, 0.3 pmol vector, 1.5 pmol fragment (approximately), 2 units of T4 DNA ligase were used (standard conditions, total volume 30 μl, incubation 4 h at 14 ° C.).

The transformation was carried out with E. coli strain RRI delta M15 as host using a third of the ligation mixture (standard conditions). A total of 173 "blue" colonies were obtained on indicator plates containing 200 µg ampicillin / ml. Of these, 12 transformants were further analyzed by rapid analytical plasmid isolation (standard conditions). Of the 173 transformants, 30 should represent background transformants as calculated from the percentage of transformants obtained by vector ligation. This result was confirmed by restriction analysis of the plasmids of the 12 transformants. Eight of them were positive by having a Bam HI - Hind III restriction fragment of approximately 200 base pairs. The positive recombinant plasmids were also linearized with Sst II, a single restriction site in the aprotinin gene. The base sequence analysis according to the standard method, as described in materials and methods, showed that the plasmid pES 44.1.1 contained the desired aprotinin DNA fragment as an insert (see FIG. 8). The plasmid pES 44.1.1 was used for further analysis and expression work. Plasmid pES 45.1.3 was constructed using exactly the same procedure using Val-15-Leu-17-Glu-39-Glu-52-aprotinin from pNH 16.1.1. The positive recombinant plasmid pES 45.1.3 showed the correct DNA sequence; this construct was used for further analysis and expression work.

Construction of plasmid pNH 05.1.1 (Val-15-Leu-17-Glu-52-aprotinin (see Figure 9) and pNH 21.1.1 (Val-15-Leu-17-Glu-39-Glu-52 -Aprotinin) was carried out using the method as shown in Fig. 9. The Val-15-Leu-17-Glu-52-aprotinin gene was obtained from pNH 02.1.1 as an EcoRI - Hind III fragment Expression vector pPLc 24 required modification of the aprotinin gene by adding a Bam HI site at the 5'-EcoRI end of the gene. This was done as described above for cloning the gene in pUR278. The modified gene was inserted into the vector pPLc 24, which had been re-stricted with Bam HI and Hind III. pPLc 24 was obtained from Prof. W. Fiers, University of Ghent, Belgium. In this construct, the aprotinin gene is linked in frame to the N-terminal part of the RNA polymerase of phage MS-2 (Remault et al, Gene 15, 81-93 (1981)). The plasmid pNH 05.1.1 was used for further analysis and expression.

The plasmid pNH 21.1.1 was obtained in the same way as pNH 05.1.1, namely by ligating the modified EcoRI / Hind III fragment, which was obtained from plasmid pNH 16.1.1, into plasmid pPL 24, which was obtained from Bam HI and Hind III had been restricted.

Example 5

Construction of the alpha-amylase secretion vector pCH 2742

For cloning in E. coli secretion vector pCH 237, the gene for Val-15-Leu-17-Met-52-aprotinin was modified by introducing an Xba I site at the codon for Arg-1. For this purpose, pRK 126.1.24 was restricted at the EcoRI site, and after filling with dNTP in the presence of DNA polymerase (large fragment), an XbaI linker (Biolabs 1010) was ligated into the restriction site (see FIG. 10) , whereby the plasmid pWB 260 was obtained. pWB 260 was restricted to XbaI and XhoI, the vector was isolated and a linker consisting of two synthetic DNA fragments (WB 14 and WB 15) was ligated into pWB 260 to give pWB 2601 (Fig. 10).

The construction of the alpha-amylase secretion vector was carried out as follows:

The alpha-amylase signal sequence in B. subtilis was obtained from Bacillus subtilis DSM 704 (German strain collection for microorganisms, Göttingen) by cloning a partial Sau3A cleavage product of the chromosomal DNA into the BamHI site of pMK 3 (MA Sullivan et al (1984 ), Gene 29, 21-26). One of the clones, which contained a 3 Kb DNA fragment with the alpha-amylase gene. was modified by deletion of portions of the alpha amylase structural gene to obtain pALK1 (personal communication from Dr. MA Courtney; University of Rochester, NY, Microbiology Department). DNA sequences from pALK1 showed a possible ribosome binding site (RBS) and a signal sequence on a 230 pb EcoRI-BstEII fragment with extensive homology to alpha-amylase from B. subtilis 1A289 (compare DNA sequence in FIG. 11 with M. Yang et al (1983), Nucleic Acid Research, 11, 237-249). Since the processing of the alpha-amylase signal sequence in E.coli takes place after the amino acid alanine in position 31 (W. Bruns, unpublished results), we introduced a NheI restriction site at ala 31. We isolated from pALK1 (by Dr. MA Courtney, Rochester) provided a 180 bp EcoRI - HaeIII fragment which contained the possible Shine-Dalgarno site and a large part of the signal sequence of alpha-amylase (fragment A in Fig. 12). Fragment B (see FIG. 12), a synthetic linker which forms the NheI site at codon 31 of the amylase signal sequence, was ligated together with fragment A (see FIG. 12) in pBR 322, which was linked to EcoRI and NheI was split (pWB 226). pWB 226 was restricted to BamHI and, after filling with dNTP, a HindIII linker (Biolabs 1002) was ligated into the vector to obtain pWB 2024.

The secretion vector pCH 237 was constructed by placing the amylase signal sequence as an ECO RI-Bam HI fragment from pWB 2024 behind the lacZ promoter in pUC 8 (FIG. 12). In this construct, the reading frame of lacZ 'should be terminated at the TAA stop codon (pos. -58 / -56 in the DNA sequence of fragment A, Fig. 11). Reinitiation of protein synthesis on the same mRNA should, after binding the ribosome to the possible Shine-Dalgarno site of alpha-amylase, approx. 50 Bases downstream of the stop codon at position -12.

To express Val-15-Leu-17-Met-52-aprotinin, the aprotinin gene was isolated as an XbaI-HindIII fragment from pWB 2601 and integrated behind the alpha-amylase signal sequence in pCH 237, restricted with NheI and HindIII, which leads to pCH 2742 (Fig. 13).

Example 6

Isolation of an MS-2-Val-15-Leu-17-Glu-39-Glu-52-aprotinin and / or an MS-2-Val-15-Leu-17-Glu-52-aprotinin fusion protein described in E .coli were expressed

For the expression of MS-2 aprotinin fusion proteins, E. coli C600 [pcI 857] was transformed with the plasmid pNH 05.1.1 or pNH 21.1.1, in a broth containing 30 g / l yeast extract, 30 g / l beef extract and 1 g / l K₂HPO₄ contained in deionized water, grown. The pH was adjusted to 7.0. 100 ml of the broth were placed in 1 liter Erlenmeyer flasks and treated in an autoclave at 121 ° C. for 20 minutes. After incubation with a seed culture which had been grown in the same medium for 8 hours at 28 ° C., the flasks were incubated on a rotary shaker at 280 rpm (diameter of the shaking motion: 5 cm) for 4 hours at 28 ° C. At this time, the absorbance of the culture was about 4 (measured at 700 nm). The temperature was then raised to 42 ° C and the incubation continued for a further 3 h. At that time the cells contained up to 15% fusion protein based on the total cell protein. The fusion protein could be visualized by standard polyacrylamide gel electrophoresis using a 17% acrylamide concentration and staining with Coomassie blue.

Heat-induced cells were collected from the culture broth by centrifugation at 5,000 rpm (Beckman JA-10) for 15 minutes, in 10 ml / g (by wet weight) buffer A (0.1 M Tris-HCl, pH 7.5, which contained 10 mM EDTA, 5 mM beta-mercaptoethanol and 5 mM benzamidine-HCl) and incubated for 30 min at 30 ° C. with 0.2 mg / ml lysozyme (approx. 100,000 units / mg, Fluka AG, Switzerland) with vigorous stirring.

The suspension was then cooled to 4 ° C and passed twice through a "French Pressure" cell (Aminco, USA) at 18,000 psi to disrupt the cell membranes. The insoluble material was recovered by centrifugation at 10,000 rpm (Beckman JA-10) for 30 minutes and the supernatant was discarded.

As described above, the pellet was resuspended twice in buffer A to which 2 M urea had been added and centrifuged. The supernatants were again discarded.

The pellet was then dissolved in 10 ml / g (wet weight) of Buffer B (0.05 M Tris-HCl pH 8.5, which contained 8 M guanidine-HCl and 10 mM beta-mercaptoethanol), the solution by 30 min Centrifugation at 18,000 rpm (Beckman JA-20) clarified and 10 ml on a column (5 x 90 cm), filled with Sephacryl S-300 (Pharmacia AB, Sweden) and in buffer C (0.05 M Tris-HCl pH 8.5, which contained 6 M urea and 10 mM beta-mercaptoethanol) was given. Fractions of 10 ml were collected and the peak containing the fusion protein was identified by SDS-PAGE under reduction conditions. The peak fractions were pooled and dialyzed extensively against water. Under these conditions, the fusion protein precipitated and was collected by centrifugation at 10,000 rpm (Beckman JA-10) for 30 minutes. The fusion protein pellets were stored at -70 ° C.

Figure 14 shows a typical separation. Fractions containing the fusion protein are indicated by a bar.

Example 7

Production of bioactive Val-15-Leu-17-Glu-52-aprotinin from purified MS-2 fusion protein

The fusion protein (prepared according to Example 6) was dissolved in about 5 ml / 100 mg (wet weight) of 70% formic acid and treated with cyanogen bromide (molar ratio methionine: CNBr = 1: 250) for 18 hours under nitrogen at room temperature (Witkop et al (1968) Science 162: 318-326). The cracking mixture was then diluted 10 to 20 times with water; Formic acid and residual CNBr were removed under reduced pressure.

The concentrated solution was titrated to pH 7.5 with 5 M NaOH and solid urea was added to a final concentration of 8 molar. After adding 25 mM beta-mercaptoethanol and 2 hours incubation at 37 ° C under nitrogen, the solution was overnight against 20 volumes of buffer D (0.05 M Na acetate pH 5.2, which was 6 M urea and 10 mM beta-mercaptoethanol contained) dialyzed at 8 ° C.

In order to renaturalize Val-15-Leu-17-Glu-52-aprotinin, the solution was placed on a column (2.5 × 5 cm) which was filled with CM-Sepharose fast flow (Pharmacia AB, Sweden) and stored in buffer D was equilibrated. The column was washed with buffer D (approx. 8 to 10 column volumes) and with a linear gradient of 150 ml buffer D and 150 ml buffer E (0.05 M Na acetate, pH 5.2, which was 2 mM beta-mercaptoethanol contained) developed, whereupon briefly with 0.05 M Na acetate pH 5.2 (approx. 2nd up to 3 column volumes). Finally, renatured Val-15-Leu-17-Glu-52-aprotinin was eluted with 0.05 M Na acetate pH 5.2, which contained 0.5 M NaCl (see FIG. 15).

The peak fractions of the NaCl eluate (identified by SDS-PAGE) were collected and dialyzed extensively against 20 mM Hepes pH 6.5 and subsequently on a Mono-S column (1 ml) equilibrated with the same buffer (FPLC , Pharmacia, Sweden). The protein was bound to the column and eluted with a linear gradient from zero to 300 mM NaCl (see FIG. 16). The peak fractions containing the aprotinin variant were collected, dialysed extensively against 0.1 M ammonium bicarbonate and lyophilized in suitable aliquots.

Usually 0.5 to 1.5 mg of purified Val-15-Leu-17-Glu-52-aprotinin was obtained per liter of culture broth.

The purified protein had the expected properties in terms of amino acid composition, linear sequence (position 1-25), molecular weight and behavior on reverse phase HPLC (FIG. 17) (see Example 9).

Example 8

Isolation of Val-15-Leu-17-aprotinin expressed in E. coli RRI M15 pCH 2742

E. coli RRI M15 transformed with pWB 2742 were grown in overnight cultures. The medium contained 3% bovine extract (Gibco), 1.5% yeast extract (Gibco), 0.5% K₂HPO₄ and 4% morpholino-ethanesulfonic acid, dissolved in distilled water. The pH was adjusted to 7.0. 100 ml of the medium were placed in 1 l Erlenmeyer flasks and treated in an autoclave at 121 ° C. for 20 min. After cooling, ampicillin, which had been dissolved in distilled water and sterilized by filtration, was added to a final concentration of 50 μg / l. To prepare Val-15-Leu-17-aprotinin, the flasks were inoculated with a culture grown overnight in the same medium at 28 ° C. The flasks were incubated on a rotary shaker at 280 rpm and 28 ° C. for 3 hours until the absorbance measured at 550 nm was approximately 1. The lac promoter was then induced by adding 1 mM isopropylthiogalactoside (Sigma) to the cultures. The fermentation was continued for 20 h and the cells were then harvested by centrifugation at 8,000 rpm (10 min 4 ° C. in Kontron Centrikon H-401 with rotor A 6.14).

The cells were homogenized in 500 ml of 0.01 M Tris buffer pH 8.0 and broken under cooling with crushed ice by ultrasonication at 400 W until more than 95% of all cells had been destroyed. 30 ml of perchloric acid (72%) was added to this suspension (700 ml) with stirring. After 30 minutes, the supernatant was collected by centrifugation (20 minutes / 6,000 rpm). It was neutralized by adding saturated Tris base solution and passed over 50 ml of gel bed anti-aprotinin antibodies (immunization against aprotinin in rabbits) which were immobilized on Sepharose CL 4B according to the BrCN method. No active material was found in the run. The gel was washed successively with 0.2 M Tris buffer pH 8.0 and water, with no activity being desorbed. The activity could be desorbed by elution with 0.2 M acetic acid, adjusted to pH 1.9 with HCl. This eluate was lyophilized and dissolved in 5 ml of 0.02 M Hepes buffer pH 6.0. Another purification was performed by FPLC on Mono S^(R) (Pharmacia, Sweden) using an increasing gradient of NaCl (0 to 0.5 M). The activity was in fractions 41-47 (see Fig. 18), which were pooled, dialyzed and lyophilized.

Example 9

Chemical protein characterization of Val-15-Leu-17-aprotinin variants

A complete amino acid analysis was performed as described in materials and methods. The results obtained which show the amino acid composition of Val-15-Leu-17-Glu-52-aprotinin, Val-15-Leu-17-Thr-52-aprotinin, Leu-15-Leu-17-Glu-52-aprotinin, Val-15-Leu-17-Glu-39-Glu 52-aprotinin and Val-15-Leu-17-Met-52-aprotinin concerned were the following: <tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="6" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" align="left">amino acid</entry><entry namest="col2" nameend="col2" align="center">1*</entry><entry namest="col3" nameend="col3" align="center">2*</entry><entry namest="col4" nameend="col4" align="center">3*</entry><entry namest="col5" nameend="col5" align="center">4*</entry><entry namest="col6" nameend="col6" align="center">5*</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Asp</entry><entry namest="col2" nameend="col2" align="char" char=",">5,09(5)</entry><entry namest="col3" nameend="col3" align="char" char=",">5,18(5)</entry><entry namest="col4" nameend="col4" align="char" char=",">5,15(5)</entry><entry namest="col5" nameend="col5" align="char" char=",">4,95(5)</entry><entry namest="col6" nameend="col6" align="char" char=",">5,13(5)</entry></row><row><entry namest="col1" nameend="col1" align="left">Thr</entry><entry namest="col2" nameend="col2" align="char" char=",">3,03(3)</entry><entry namest="col3" nameend="col3" align="char" char=",">3,89(4)</entry><entry namest="col4" nameend="col4" align="char" char=",">2,83(3)</entry><entry namest="col5" nameend="col5" align="char" char=",">2,81(3)</entry><entry namest="col6" nameend="col6" align="char" char=",">2,87(3)</entry></row><row><entry namest="col1" nameend="col1" align="left">Ser</entry><entry namest="col2" nameend="col2" align="char" char=",">1,19(1)</entry><entry namest="col3" nameend="col3" align="char" char=",">1,13(1)</entry><entry namest="col4" nameend="col4" align="char" char=",">1,02(1)</entry><entry namest="col5" nameend="col5" align="char" char=",">1,15(1)</entry><entry namest="col6" nameend="col6" align="char" char=",">1,01(1)</entry></row><row><entry namest="col1" nameend="col1" align="left">Glu</entry><entry namest="col2" nameend="col2" align="char" char=",">4,43(4)</entry><entry namest="col3" nameend="col3" align="char" char=",">3,31(3)</entry><entry namest="col4" nameend="col4" align="char" char=",">4,44(4)</entry><entry namest="col5" nameend="col5" align="char" char=",">5,57(5)</entry><entry namest="col6" nameend="col6" align="char" char=",">3,20(3)</entry></row><row><entry namest="col1" nameend="col1" align="left">Ala</entry><entry namest="col2" nameend="col2" align="char" char=",">6,00(6)</entry><entry namest="col3" nameend="col3" align="char" char=",">6,00(6)</entry><entry namest="col4" nameend="col4" align="char" char=",">6,00(6)</entry><entry namest="col5" nameend="col5" align="char" char=",">5,84(6)</entry><entry namest="col6" nameend="col6" align="char" char=",">6,31(6)</entry></row><row><entry namest="col1" nameend="col1" align="left">Gly</entry><entry namest="col2" nameend="col2" align="char" char=",">6,28(6)</entry><entry namest="col3" nameend="col3" align="char" char=",">5,86(6)</entry><entry namest="col4" nameend="col4" align="char" char=",">5,84(6)</entry><entry namest="col5" nameend="col5" align="char" char=",">5,92(6)</entry><entry namest="col6" nameend="col6" align="char" char=",">6,02(6)</entry></row><row><entry namest="col1" nameend="col1" align="left">Val</entry><entry namest="col2" nameend="col2" align="char" char=",">2,13(2)</entry><entry namest="col3" nameend="col3" align="char" char=",">1,97(2)</entry><entry namest="col4" nameend="col4" align="char" char=",">0,98(1)</entry><entry namest="col5" nameend="col5" align="char" char=",">2,00(2)</entry><entry namest="col6" nameend="col6" align="char" char=",">1,87(2)</entry></row><row><entry namest="col1" nameend="col1" align="left">Mead</entry><entry namest="col2" nameend="col2" align="char" char=",">----(-)</entry><entry namest="col3" nameend="col3" align="char" char=",">----(-)</entry><entry namest="col4" nameend="col4" align="char" char=",">----(-)</entry><entry namest="col5" nameend="col5" align="char" char=",">----(-)</entry><entry namest="col6" nameend="col6" align="char" char=",">0,88(1)</entry></row><row><entry namest="col1" nameend="col1" align="left">Ile</entry><entry namest="col2" nameend="col2" align="char" char=",">1,45(2)</entry><entry namest="col3" nameend="col3" align="char" char=",">1,35(2)</entry><entry namest="col4" nameend="col4" align="char" char=",">1,39(2)</entry><entry namest="col5" nameend="col5" align="char" char=",">1,42(2)</entry><entry namest="col6" nameend="col6" align="char" char=",">1,28(2)</entry></row><row><entry namest="col1" nameend="col1" align="left">Leu</entry><entry namest="col2" nameend="col2" align="char" char=",">2,97(3)</entry><entry namest="col3" nameend="col3" align="char" char=",">2,87(2)</entry><entry namest="col4" nameend="col4" align="char" char=",">3,87(4)</entry><entry namest="col5" nameend="col5" align="char" char=",">2,89(3)</entry><entry namest="col6" nameend="col6" align="char" char=",">2,90(3)</entry></row><row><entry namest="col1" nameend="col1" align="left">Tyr</entry><entry namest="col2" nameend="col2" align="char" char=",">3,73(4)</entry><entry namest="col3" nameend="col3" align="char" char=",">3,64(4)</entry><entry namest="col4" nameend="col4" align="char" char=",">3,73(4)</entry><entry namest="col5" nameend="col5" align="char" char=",">3,09(4)</entry><entry namest="col6" nameend="col6" align="char" char=",">3,58(4)</entry></row><row><entry namest="col1" nameend="col1" align="left">Phe</entry><entry namest="col2" nameend="col2" align="char" char=",">3,83(4)</entry><entry namest="col3" nameend="col3" align="char" char=",">3,83(4)</entry><entry namest="col4" nameend="col4" align="char" char=",">3,83(4)</entry><entry namest="col5" nameend="col5" align="char" char=",">3,69(4)</entry><entry namest="col6" nameend="col6" align="char" char=",">3,83(4)</entry></row><row><entry namest="col1" nameend="col1" align="left">Lys</entry><entry namest="col2" nameend="col2" align="char" char=",">2,84(3)</entry><entry namest="col3" nameend="col3" align="char" char=",">2,79(3)</entry><entry namest="col4" nameend="col4" align="char" char=",">2,92(3)</entry><entry namest="col5" nameend="col5" align="char" char=",">2,85(3)</entry><entry namest="col6" nameend="col6" align="char" char=",">2,80(3)</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Arg</entry><entry namest="col2" nameend="col2" align="char" char=",">4,82(5)</entry><entry namest="col3" nameend="col3" align="char" char=",">4,76(5)</entry><entry namest="col4" nameend="col4" align="char" char=",">4,95(5)</entry><entry namest="col5" nameend="col5" align="char" char=",">3,79(4)</entry><entry namest="col6" nameend="col6" align="char" char=",">4,77(5)</entry></row></tbody></tgroup><tgroup cols="6" colsep="0" rowsep="0"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><tbody valign="top"><row><entry namest="col1" nameend="col6" align="justify">1 * Val-15-Leu-17-Glu-52-aprotinin</entry></row><row><entry namest="col1" nameend="col6" align="justify">2 * Val-15-Leu-17-Thr-52-aprotinin</entry></row><row><entry namest="col1" nameend="col6" align="justify">3 * Val-15-Leu-17-Glu-52-aprotinin</entry></row><row><entry namest="col1" nameend="col6" align="justify">4 * Val-15-Leu-17-Glu-39-Glu-52-aprotinin</entry></row><row><entry namest="col1" nameend="col6" align="justify">5 * Val-15-Leu-17-Met-52-aprotinin</entry></row></tbody></tgroup></table></tables> Cys and Pro were not determined.

The N-terminal amino acid sequence was determined as indicated in materials and methods. The amino acid sequence as obtained after 25 cycles was as follows:<img file="EP0307592A2_D0003.tif" />

Approx. 30% of the Val-15-Leu-17-Met-52-aprotinin obtained by fermentation in E.coli RR1 ΔM15 pCH 2742 contained an additional Ala residue at the N-terminus. This can be prevented by replacing Ala-30 with Gln in the alpha-amylase signal sequence (see FIG. 11).

Example 10

Determination of the kinetic constants of Val-15-Leu-17-aprotinin variants

The K_i- Values ​​were determined as stated in materials and methods. The inhibition of human leukocyte elastase (HLE) by increasing amounts of Val-15-Glu-52 and Val-15-Leu-17-Glu-52-aprotinin is shown in FIG. 18. Typical K_iValues ​​for the inhibition of human leukocyte elastase, human pancreatic elastase I and human cathepsin G, as obtained with aprotinin variants, are as follows: <tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="4" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="39.37mm" /><colspec colnum="2" colname="col2" colwidth="39.37mm" /><colspec colnum="3" colname="col3" colwidth="39.37mm" /><colspec colnum="4" colname="col4" colwidth="39.37mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">Human leukocyte elastase</entry><entry namest="col3" nameend="col3" align="center">K_i (M) Human pancreatic elastase I</entry><entry namest="col4" nameend="col4" align="center">Human Cathepsin G</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Val-15-Glu-52</entry><entry namest="col2" nameend="col2" align="right">1.5x10⁻¹⁰</entry><entry namest="col3" nameend="col3" align="right">-</entry><entry namest="col4" nameend="col4" align="right">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Val-15-Leu-17-Glu-52</entry><entry namest="col2" nameend="col2" align="right">5-6x10⁻¹¹</entry><entry namest="col3" nameend="col3" align="right">&gt;10⁻⁶</entry><entry namest="col4" nameend="col4" align="right">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Val-15-Leu-17-Glu -39-Thr-52</entry><entry namest="col2" nameend="col2" align="right">2x10⁻¹⁰</entry><entry namest="col3" nameend="col3" align="right">5x10⁻⁹</entry><entry namest="col4" nameend="col4" align="right">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Val-15-Leu-17-Met-52</entry><entry namest="col2" nameend="col2" align="right">6x10⁻¹¹</entry><entry namest="col3" nameend="col3" align="right">&gt;10⁻⁶</entry><entry namest="col4" nameend="col4" align="right">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Val-15-Leu-17-Thr-52</entry><entry namest="col2" nameend="col2" align="right">7x10⁻¹¹</entry><entry namest="col3" nameend="col3" align="right">&gt;10⁻⁶</entry><entry namest="col4" nameend="col4" align="right">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Leu-15-Leu-17-Glu-52</entry><entry namest="col2" nameend="col2" align="right">1x10⁻¹⁰</entry><entry namest="col3" nameend="col3" align="right">&gt;10⁻⁷</entry><entry namest="col4" nameend="col4" align="right">2x10⁻⁸</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Leu-15-Leu-17-Glu-39-Glu-52</entry><entry namest="col2" nameend="col2" align="right">2x10⁻⁹</entry><entry namest="col3" nameend="col3" align="right">1x10⁻⁹</entry><entry namest="col4" nameend="col4" align="right">1x10⁻⁹</entry></row></tbody></tgroup></table></tables>