EVALUATION OF PYRIMIDINE-DEGRADING AND HYDANTOIN-DEGRADING ENZYME-ACTIVITIES IN AEROBIC-BACTERIA

The enzyme activities responsible for the reductive pyrimidine base degradation by aerobic bacteria, which, produce hydantoin-degrading enzymes, were investigated. Pseudomonas putida IFO 12996, which is a D-stereospecific hydantoinase producer, has dihydropyrimidinase activity, and Comamonas sp. E222c and Blastobacter sp. A17p-4, which are N-carbamoyl-D-amino acid amidohydrolase producers, have beta-ureidopropionase activity. Blastobacter sp. also possesses both D-stereospecific hydantoinase and dihydropyrimidinase activities. Thus, two amide ring-opening activities and/or two N-carbamoyl amino acid-hydrolyzing activities coexist in these bacteria. However, the differences of the induction levels of each enzyme activities for the several pyrimidine- and hydantoin-related compounds suggest that these corresponding amide ring-opening or N-carbamoyl amino acid-hydrolyzing activities are not always catalyzed by the same enzymes.