STUDIES ON THE ASYMMETRICAL HYDROLYSIS OF N^α, N^ε-DIACYL-DL-LYSINE

Abstract

Three different kinds of acylases, α-lysine acylase, ε-lysine acylase and D-phenylalanine acylase, capable of performing the resolution of acyl-DL-amino acids, are produced by a Pseudomonas species, KT-83, which was previously isolated from soil by Kameda et al. One of these enzymes, ε-lysine acylase, was purified by treatment with ion exchange resin and by fractionation with ammonium sulfate. The purified enzyme does not possess the activity of the α-lysine acylase, but it has a specific activity against N^ε-benzoyl-L-lysine, representing about 4, 000-fold purification of the activity in the original extract. The α-lysine acylase has an optimum pH at 7.8 and the ε-lysine acylase at 6.0. The optimum temperature of both the a-and ε-lysine acylase is 37-38°. Among a variety of ions Zn⁺⁺ at 10^-3 M concentration increases the activity of the ε-lysine acylase against N'-benzoyl-DL-lysine. The purified enzyme was shown by electrophoresis to contain two protein fractions.
The enzyme hydrolyzes asymmetrically N^ε acyl-DL-lysine easily, but is unable to hydrolyze N^α, N^ε-diacyl-DL-lysine. From these facts, the asym-metrical hydrolysis of N^α N^ε-diacyl-DL-lysine by the crude acylase preparation of KT-83 is considered to proceed as follows; N^α, N^ε-diacyl-DL-lysine is first hydrolyzed asymmetrically by the α-lysine acylase to N^α-acyl-L-lysine, which is then hydrolyzed to L-lysine by the ε-lysine acylase.
The author wishes to express their appreciation to Dr. S. Kuwada, Dr. S. Tatsuoka and Dr. Y. Kameda for their great favor and continuous interest.
Thanks are also due to Dr. E. Ohmura, Mr. A. Miyake and Dr. K. Ogata for their support, and to Mr. I. I mad a and Mr. K. Tomoda for their technical help.