Reaction mechanism for the conversion of 5-monosubstituted hydantoins to enantiomerically pure L-amino acids.

The specific conversion of D,L-5-monosubstituted hydantoins to optically pure L-amino acids by resting cells of Arthrobacter sp. DSM 7330 has been evaluated. A new nonstereoselective hydantoinase from Arthrobacter sp. DSM 7330 was isolated and characterized. When whole cells were tested, the conversion of D,L-5-methylthioethylhydantoin (D,L-5-MTEH) led to the optically pure intermediate D-carbamoylmethionine (D-CM) and to the optically pure amino acid L-methionine. After purification of the hydantoin hydrolyzing enzyme, the probable reaction mechanism of the conversion of 5-monosubstituted hydantoins to enantiomerically pure L-amino acids could be enlightened.