Abstract
Cysteine desulfhydrase from Aerobacter aerogenes degrades β-chloro-L-alanine into pyruvate, ammonia and hydrochloric acid, at the higher rate compared with that for L-cysteine. In the presence of hydrogen sulfide, the enzyme catalyzes β-replacement reaction of the amino acid to synthesize L-cysteine. When hydrogen sulfide is replaced by alkyl- or allyl-mercaptans in this reaction, the corresponding S-substituted L-cysteines were synthesized. The enzymatically synthesized L-cysteine and S-substituted L-cysteines were isolated from the large scale reaction mixtures and identified by physicochemical meanings.
