辅酶四氢叶酸的合成及其活力测定

Synthesis of Coenzyme THFA and Determination of Its Relative Activity

在利用基因工程菌表达的丝氨酸羟甲基转移酶 (SHMT)酶法制备L 丝氨酸的过程中 ,SHMT需要四氢叶酸作为辅酶。研究了常压氢化法、加压氢化法、硼氢化物还原法及连二亚硫酸钠还原法等制备四氢叶酸 ,并优化了常压氢化法、硼氢化物还原法的工艺条件。常压氢化法的产品已用来代替进口试剂作为酶促反应的辅酶 ,但硼氢化物还原法成本最低 ,且能合成满足酶促反应要求的产物。四氢叶酸在制备过程和使用中 ,均极易氧化破坏 ,因此需提供严格的抗氧化条件。

SHMT enzymatic preparation of L ser requires THFA as its coenzyme, the enzyme SHMT is expressed by genetically engineered bacteria Reduction of FA is the common synthetic method of THFA These methods include hydrogenation in high pressure,reduction by hydroborates and reduction by dithionite This article studied these methods, especially optimized the technology of hydrogenation in normal pressure and reduction by hydroborates The THFA product of hydrogenation in common pressure has been used in enzymatic reaction and expressed the same result as that of THFA from Sigma, the cost of reduction by hydroborates is lower THFA is oxygenated and destroyed easily during preparation and application Thus, anti oxidation condition is necessary