色氨酸合成酶酶法合成S-苯基-L-半胱氨酸的研究

Enzymatic Synthesis of S-phenyl-L-cysteine Catalyzed by Tryptophan Synthase

摘要:

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影响。最佳转化条件为：反应温度为37 篊，pH为8，L-丝氨酸与苯硫酚的适宜底物摩尔比为1:1.2，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。

Abstract:

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 ºC 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, bioconversion rate of L-serine reached 91% after 16 h. The stable hydrogen bonds were formed between thiopheno and tryptophan synthase active site Ser235 and Gly233.