Deblocking the common pathway of aromatic amino acid synthesis.

(57) Improvement in efficiency of production in the host cell of the aromatic compounds which go via the common course shown in the summary figure 1 is realized by raising the revelation of the enzyme kind which acts on substrate intermediate field in the rate determining step identified on the course. Although a host cell is transformed by recombinant DNA which carries out the code of the 律速 enzyme and brings about a cell transformation object, when it grows in the cell culture which has a source of carbon in which metabolism is possible, as for this transformation object, it is characterized by having the capability to produce a high-concentration aromatic series metabolic product.