Stabilized bioactive peptides and methods of identification, synthesis and use

(57) The selection system in a summary cell makes possible simultaneous screening of the biological activity of peptide, and stability. In the revelation system which originates in a wild type lac operon preferably and which was adjusted strictly, randomization recombination peptide is screened about biological activity. In this way, the identified bioactive peptide is protease tolerance and peptidase tolerance peculiar. Moreover, bioactive peptide stable with the stabilization machine in N end, C end, or both is offered. A stabilization machine can be chosen from small stable protein, for example, Rop protein, a glutathione スルホ transferase, チオレドキシン, malt sugar unity protein, glutathione reductase, 1, or the proline residue beyond it.