Synthesis of D-Cysteine from a Racemate of 3-Chloroalanine by Phenylhydrazine-treated Cells of Pseudomonas putida CR 1-1

Abstract

3-Chloro-D-alanine chloride-lyase, which occurs in the cells of Pseudomonas putida CR 1-1, catalyzes the β-replacement reaction of 3-chloro-D-alanine in the presence of a high concentration of sodium hydrosulfide to form D-cysteine. Using the β-replacement reaction, the synthesis of D-cysteine from a racemate of 3-chloroalanine by resting cells was investigated. In order to depress the synthesis of L-cysteine from 3-chloro-L-alanine and the enzymatic degradation of 3-chloro-L-alanine, treatment of the cells with 5mM phenylhydrazine was utilized. Under the optimal conditions, 94% of the added 3-chloro-D-alanine could be converted to D-cysteine and 81% of the added 3-chloro-L-alanine was recovered.