| 摘要 |
PURPOSE: To obtain the subject new DNA fragment having a specific amino acid sequence, coding a dihydroxy acid dehydratase relating to the bio-synthesis of L-isoleucine and L-valine in living bodies, and capable of being utilized for the production of the amino acids. CONSTITUTION: This new DNA fragment has an amino acid sequence containing an amino acid sequence of the formula, contains a gene coding a dihydroxy acid dehydratase originated from a Corynebacterium type bacterium [e.g. Brevibacterium fulvum MJ-233 (FERM BP-1497], has Kpn I sites at both the ends, has a size of 6.0-Kb, relates to the biosynthesis of L-isoleucine and L-valine in living bodies, and can be utilized for the production of the amino acids. The DNA fragment is obtained by culturing the Brevibacterium fulvum MJ-233 until the final period of a logarithmic growth phase, collecting the cultured bacteria, extracting whole DNA from the collected bacteria by a conventional method, treating the extract with a restriction enzyme, ligating the obtained fragment to a vector, introducing the vector into a host, screening the cultured hosts, and subsequently recovering the DNA from the positive stains. |
