Cystathionine γ-lyase (EC 22.214.171.124) occurring in Streptomyces phaeochromogenes (IFO 3105) can catalyze not only the α,γ-elimination reaction of l-homoserine to form α-ketobutyrate and ammonia but also the γ-replacement reaction of l-homoserine in the presence of l-cysteine to form l-cystathionine. Optimal reaction conditions for the enzymatic synthesis of l-cystathionine using the γ-replacement reaction were defined. Since concentrations of greater than 10 mM l-cysteine inhibit the γ-replacement reaction, it is necessary to keep the concentration of l-cysteine around 10 mM for a high yield of l-cystathionine. Under optimal reaction conditions, defined as the conditions producing the highest yield, 1.39 mmol of lcystathionine (0.3 g) was synthesized enzymatically from 20 mmol of l-homoserine and 5.8 mmol of l-cysteine in 100 ml of reaction mixture.
- Streptomyces phaeochromogenes
- cystathionine γ-lyase
- pyridoxal-phosphate dependent enzyme
- γ-replacement reaction
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology