水/有机溶剂双相体系中色氨酸合成酶酶法合成2-甲基-L-色氨酸

Enzymatic Synthesis of L-2-Methyltryptophan Catalyzed by Tryptophan Synthase in a Water/Organic Solvent Biphase System

本文作者研究了水/有机溶剂双相体系中利用色氨酸合成酶催化L-丝氨酸和2-甲基吲哚合成2-甲基-L-色氨酸,考察了有机溶剂、有机溶剂体积分数、p H、反应温度、表面活性剂、金属离子和底物浓度对色氨酸合成酶催化合成2-甲基-L-色氨酸的影响。有机溶剂包括二甲苯、甲苯、乙酸乙酯、乙酸丁酯和辛醇,表面活性剂包括吐温80、聚乙二醇辛基苯基醚(OP)、CTAB和Trion X-100,金属离子包括Mg2+、Ca2+、Cu2+、Co2+和Zn2+。结果表明,酶法最佳转化条件为:有机相溶剂为甲苯,甲苯体积分数为2%,反应温度为40℃,水相p H为8,底物L-丝氨酸浓度为150mmol/L,表面活性剂Trion X-100质量分数为2%,金属离子Ca2+浓度为0.1 mmol/L,色氨酸合成酶酶促反应5 h,2-甲基-L-色氨酸的质量浓度为21.17 g/L。重组大肠杆菌DM206可作为2-甲基-L-色氨酸生产菌,具有较好的2-甲基-L-色氨酸生产潜力。

L-2-methyltryptophan plays an important role in many physiological processes. This paper investigated the synthesis of L-2-methyltryptophan in an aqueous/organic biphasic system,and optimized the synthetic method. The optimal transformation conditions were 150 mmol/L L-serine,2% toluene,0.1 mmol/L Ca^2＋,2% Trion X-100,40 ℃ and pH 8,which resulted in a content of over 21.17 g/L for L-2-methyltryptophan. Thus,the strain can be used to produce L-2-methyltryptophan and has an excellent converting capability of L-2-methyltryptophan.