PRODUCTION OF D-AMINO ACIDS FROM D,L-5-SUBSTITUTED HYDANTOINS BY AN AGROBACTERIUM-TUMEFACIENS STRAIN AND ISOLATION OF A MUTANT WITH INDUCER-INDEPENDENT EXPRESSION OF HYDANTOIN-HYDROLYZING ACTIVITY

Conversion of D,L-p-hydroxyphenylhydantoin to D-p-hydroxyphenylglycine by Agrobacterium tumefaciens RU-OR involved a racemase, an hydantoina se and an unusual D-selective N-carbamylamino acid amidohydrolase whic h was active at alkaline pH and was not inhibited by N-carbamyl-L-amin o acids. Enzyme activity was induced by growth in media containing 2-t hiouracil. A mutant strain (RU-ORL5) was isolated, which expressed bot h the hydantoinase and N-carbamylamino acid amidohydrolase enzymes in the absence of inducer.