Ketogruppe-introduserende enzym, DNA som koder for samme, samt fremgangsmåte for fremstilling av ketokarotenoid

摘要

A polypeptide having the enzymatic activity of converting the 4-methylene group of a beta -ionone compound into a keto group; a DNA containing the base sequence coding for the above polypeptide; another DNA which hybridizes with the above DNA and contains the base sequence coding for the above polypeptide; still another DNA which has been inserted into plasmid pHP51 and contains the base sequence coding for the above polypeptide; a recombinant vector containing the above DNA(s); a microbe having the above DNA(s) introduced thereinto; and a process for producing a ketocarotenoid which comprises culturing the above microbe in a medium and separating the formed ketocarotenoid from the product of culture. The introduction of the above DNAs as foreign genes into microbes, such as E. coli, followed by expression thereof makes it possible to impart to the microbes the capability of biosynthesis of astaxanthin, 4-ketozeaxanthin, canthaxanthin, echinenone and other ketocarotenoids. The use of such microbes makes it possible to mass-produce ketocarotenoids at reduced cost and labor.