S-腺苷甲硫氨酸(S-adenosyl-L-methionine,SAM)是一种具有广阔应用前景的活性氨基酸,利用毕赤酵母催化合成是SAM主要生产方法,但SAM可被细胞转化为还原型谷胱甘肽(glutathione reduced,GSH),后者可进一步转化为氧化型谷胱甘肽(glutathione oxidized,GSSG)。该研究分析了SAM合成过程中谷胱甘肽总量的动态变化,并基于GSSG/GSH偏移,揭示了胞内氧化还原势与GSH流量变化的相关性。最后添加抗氧化剂维生素C,通过降低胞内SAM→GSH流量及改善细胞活性,进一步提高SAM产率。

S-adenosyl-L-methionine(SAM) was a type of active amono acid,which is of broad prospects in application,and biosynthesis employing Pichia pastoris was the main manufacture method,while during the process,SAM was easily converted to glutathione(GSH),which could be further converted to glutathione oxidized(GSSG).The present study analyzed the dynamic changes of total GSH levels,and revealed the relationship between Redox potential and GSH flux,on the basis of analysis of the ratio of GSSG to GSH.Later,the antioxidant Vitamine C was added,the flux from SAM to GSH was reduced and cell acticity was improved.Consequently,SAM productivity was further elevated.