色氨酸合成酶酶法合成S-苯基-L-半胱氨酸

Enzymatic Synthesis of S-Phenyl-L-Cysteine Catalyzed by Tryptophan Synthase

利用重组色氨酸合成酶催化合成S-苯基-L-半胱氨酸,考察了反应温度、pH、底物摩尔比和底物浓度对色氨酸合成酶酶活的影响。最佳转化条件为:反应温度为37℃,pH=8,苯硫酚与L-丝氨酸的适宜底物摩尔比为1.2∶1,底物最适合浓度为400 mmol/L,反应达到平衡时间为16 h,底物L-丝氨酸摩尔转化率达到91%,苯硫酚与色氨酸合成酶活性位点Ser 235和Gly 233形成稳定的氢键。

Enzymatic synthesis of S-phenyl-L-cysteine from L-serine and thiopheno catalyzed by tryptophan synthase from recombinant Escherichia coli were studied. The factors such as temperature, pH, molar ratio of L-serine to thiopheno and substrate concentration were investigated. The optimal temperature and pH value were 37℃ and 8, respectively. The optimal molar ratio of L-serine to thiopheno was 1 ： 1.2. The optimal substrate concentration of L-serine was 400 mmol/L. Under the optimal conditions,the bioconversion rate of L-serine reached 91% after 16 h. The stable hydrogen bonds were formed between thiopheno and the active sites Ser235 and Gly233 of tryptophan synthase.