THE FATE OF THE CARBOXYL OXYGENS DURING D-PROLINE REDUCTION BY CLOSTRIDIAL PROLINE REDUCTASE

D-Proline is converted to B-amino valeric acid by D-proline reductase. This conversion involves the reductive cleavage of the nr-carbon-nitrogen bond. We have examined the fate of the carboxyl oxygen atoms during conversion of D-proline to delta-NH2-valeric acid. O-18 atoms from the carboxyl group of D-proline are not lost during conversion to product. In contrast, in the conversion of glycine to acetyl phosphate by glycine reductase a carboxyl oxygen atom is lost to solvent. An intermediate acyl-enzyme is found during the reduction of glycine. We conclude that the reduction of proline proceeds without the formation of an acyl enzyme intermediate. (C) 1994 Academic Press, Inc.