【摘要】 优化了重组毕赤酵母表达的S-腺苷甲硫氨酸合成酶催化L-甲硫氨酸(Met)和ATP合成S-腺苷甲硫氨酸的条件,确定了该酶的最适酶活力检测条件为20mmol/L的L-Met,26mmol/L的ATP,52mmol/L的MgCl2,300mmol/L的KCl,8mmol/L的还原型谷胱甘肽,100mmol/L的Tris,反应液pH 8.5,35°C反应1h,比活力达到23.84U/mg。该酶还可以催化以DL-Met代替L-Met为底物的S-腺苷甲硫氨酸合成反应,以降低生产成本。更多还原

【Abstract】 The catalysis conditions for S-adenosylmethionine(SAM) synthetase produced from the recombinant methylotrophic yeast Pichia pastoris were investigated. The synthetase catalyzed the biosynthesis of SAM from Lmethionine and ATP.SAM synthetase activity was assayed at 35°C for 1h in the reaction buffer containing 20 mmol/L L-Met,26 mmol/L ATP,52 mmol/L MgCl2,300 mmol/L KCl,8 mmol/L reduced glutathione,100 mmol/L Tris.The pH of the reaction solution was adjusted to 8.5 using 1mol/L KOH.The specific activity of SAM synthetase was 23.84 U/mg.Racemic DL-Met instead of LMet could be employed as the substrate for the synthesis of SAM to reduce cost.更多还原