Effect of organic solvents on enantioselectivity of protease catalysis

✍ Scribed by Katsuhiro Kawashiro; Hideki Sugahara; Shigeru Sugiyama; Hiromu Hayashi

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 126 KB
• Volume: 53
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(19970105)53:1<26::aid-bit5>3.0.co;2-0

✦ Synopsis

The protease-catalyzed transesterifications between Ntrifluoroacetyl-DL-phenylalanine 2,2,2-trifluoroethyl ester and 1-propanol were studied in a variety of anhydrous organic solvents at 30°C. The protease preparations lyophilized from phosphate buffer solutions (pH 8.0) were used as catalysts. The organic solvent affected both rate of reaction and enantioselectivity differently. Proteases such as Aspergillus oryzae protease, subtilisin Carlsberg, and subtilisin BPNЈ always preferred the L-enantiomer in both hydrophilic and hydrophobic solvents, indicating no inversion of the L-specificity in hydrophobic solvents such as toluene. However, enantioselectivity was rather poor, with E (enantiomeric ratio) values not exceeding even one order of magnitude except for acetonitrile. There was a weak inverse correlation between E values of subtilisin Carlsberg and solvent hydrophobicity (logP). Acetonitrile was a preferable solvent in terms of both rate of reaction and enantioselectivity (E = 15 to 25) for processing L-amino acid derivatives in organic media. Organic solvents generally have potential advantages of processing D-amino acid derivatives.