| 摘要 |
PROBLEM TO BE SOLVED: To obtain a novel D-aminoacylase that can simply and efficiently produce the corresponding D-amino acid from an N-acetyl-DL-amino acid. SOLUTION: This D-aminoacylase originates from a microorganism in Sebekia and has the following physical and chemical properties: it acts on an N-acetyl-D- amino acid to give D-amino acid; Molecular weight: 55,000 dalton according to the SDS-polyacryl-amide gel electrophoresis, 36,000-37,000 dalton according to the gel filtration technique; the substrate specificity: it act on N-acetyl-D- methionine, N-acetyl-D-valine, N-acetyl-D-leucine and the like, but does not acts on N-acetyl-L-methionine, N-acetyl-L-leucine, N-acetyl-L-valine; the optimal temperature: 45 deg.C in the case of the reaction at 7.5 pH; the optimal pH: 7.5-8.5 in the case of the reaction at 30 deg.C for 5 minutes; Influence of metal ion: it needs no metal ion, the activity of the enzyme is inhibited by 1 mM of Cu<2+> , Hg<2+> , Ni<2+> , Fe<2+> , Co<2+> , and Zn<2+> . |
