酶法转化DL-ATC合成L-半胱氨酸的酶促反应条件研究

Study on Enzymatic Reaction Conditions of Conversion of DL-ATC to L-cysteine

目的:考察酶源保存方式、酶促反应时间、底物pH值、底物浓度、酶浓度、金属离子等因素对酶活力的影响。方法:以假单胞菌(Pseudomonassp.)TS1138为供试菌株,采用酸式茚三酮法测定L-半胱氨酸含量,研究了酶法转化DL-ATC合成L-半胱氨酸的酶促反应条件。结果:TS1138菌株中L-半胱氨酸脱巯基酶具有较高的活性,而且Mg2+、Mn2+、Fe2+、Zn2+、Cu2+等5种金属离子对DL-ATC水解酶酶系有不同程度的抑制,其中Cu2+对该酶系的抑制作用很大。结论:确定了TS1138菌株酶法转化DL-ATC合成L-半胱氨酸的最适酶促反应条件,为酶促反应动力学的研究奠定了基础。

Objective： To examine the effect of measures for conservation of enzyme, reaction time, pH, substrate concentration, enzyme concentration and metal ion on enzyme activity. Methods： Pseudomonas sp. TS1138 was used as the Lest strain to produce L-cysteine. Concentration of L-cysteine was measured by acidic ninhydfin reaction. Enzymatic reaction of conversion of DL-ATC to L-cysteine was studied. Results： L-cysteine desulfhydrase in Pseudomonas sp. TSl138 had high activity. Mg^2＋, Mn^2＋, Fe^2＋, Zn^2＋ and Cu^2＋ had different inhibition effects on the enzyme of conversion of DL-ATC to L-cysteine. Moreover, Cu^2＋ had strong inhibition effects on the enzyme. Conclusion： Enzymatic reaction conditions of conversion of DL-ATC to L-cysteine are confirmed.