Patent ID: 6902915

Claim:
A method for producing a D-amino acid comprising contacting a heat-stable D-aminoacylase with an N-acyl-D-amino acid selected from the group consisting of N-acetyl-D-methionine, N-acetyl-D-tryptophan, N-acetyl-D-phenylalanine, N-acetyl-D-valine, N-acetyl-D-alanine, and N-acetyl-D-leucine to produce the corresponding D-amino acid, and recovering said D-amino acid, wherein said D-aminoacylase has the following physicochemical properties: (a) acts on N-acyl-D-amino acids selected from the group consisting of N-acetyl-D-methionine, N-acetyl-D-tryptophan, N-acetyl-D-phenylalanine, N-acetyl-D-valine, N-acetyl-D-alanine, and N-acetyl-D-leucine to produce the corresponding D-amino acid; (b) thermal stability such that it is stable at 55° C. when heated at pH 7.5 for 60 minutes and is inactivated at 70° C. or higher under the same condition; (c) optimal temperature of about 60° C. at pH 7.5; (d) molecular weight of about 40,000 daltons when determined by SDS-polyacrylamide gel electrophoresis; (e) optimal pH of about 7.0 at 30° C.; (f) metal ion effect such that the presence of 1 mM Co 2+ promotes activity; and (g) metal ion effect such that the presence of 1 mM Cu 2+ inhibits activity, wherein said D-aminoacylase is derived from a microorganism belonging to the genus Streptomyces.