中文摘要：

利用转录组学分析手段结合生理生化特性来研究酿酒酵母突变株高产谷胱甘肽的潜在机制。结果表明：突变株谷胱甘肽合成限速酶、抗氧化酶活力及其编码基因表达量、过氧化氢和还原型辅酶Ⅱ（nicotinamideadeninedinucleotidephosphate，NADPH）含量显著提高；丙酮酸激酶活力、丙酮酸、柠檬酸和琥珀酸含量显著降低；此外，三羧酸循环和磷酸戊糖途径的基因表达量分别显著下调和上调。因此，突变株可能在遭受内源性活性氧过氧化氢的胁迫下，通过调节谷胱甘肽合成限速酶活力加强了谷胱甘肽的合成，与抗氧化酶共同抵御氧化胁迫；丙酮酸激酶活力减弱降低了丙酮酸的合成，减少了三羧酸循环的通量，使得磷酸戊糖途径通量增加，从而提高了NADPH含量，为谷胱甘肽的合成提供了充足的还原力。

英文摘要：

The potential mechanism for glutathione oversynthesis in the Saccharomyces cerevisiae mutant Y518wasresearched using transcriptome analysis combined with physiological and biochemical characteristics.The results indicatedthat the rate-limiting enzyme of glutathione synthesis,antioxidant enzymes activities and the expression levels of theirencoding genes,and the contents of hydrogen peroxide and nicotinamide adenine dinucleotide phosphate(NADPH)weresignificantly increased in the mutant whereas pyruvatekinase activity,the contents of pyruvate,citrate and succinate were markedlydecreased.Besides,the expression levels of genes involved in the citrate cycle were significantly down-regulated while thoseinvolved in the pentose phosphate pathway were significantly up-regulated.Therefore,under endogenous oxidative stress,themutant might strengthen the synthesis of glutathione by adjusting the activities of rate-limiting enzymes of glutathione synthesisto defend against oxidative stress together with the antioxidant enzymes.Meanwhile,weakened pyruvatekinase activity decreasedpyruvate generation,which led to declined citrate cycle flux and increased NADPH production by the pentose phosphate pathwayand consequently provided appropriate reducing power for glutathione biosynthesis.