光滑球拟酵母中α-酮戊二酸脱氢酶系生理作用解析  

Physiological function of α-ketoglutarate dehydrogenase complex in Torulopsis glabrata

作　　者：张旦旦[1] 刘立明[2,1] 堵国成[1] 陈坚[2,1] 

机构地区：[1]江南大学工业生物技术教育部重点实验室,无锡214122 [2]江南大学食品科学与技术国家重点实验室

出　　处：《微生物学报》2009年第12期1584-1589,共6页Acta Microbiologica Sinica

基　　金：国家杰出青年基金(20625619);国家"863计划"(2006AA02Z201);国家自然科学基金(30670066;20706025)~~

摘　　要：【目的】研究α-酮戊二酸脱氢酶系在光滑球拟酵母碳代谢流、能量代谢和氨基酸代谢中的生理作用。【方法】通过敲除光滑球拟酵母中编码α-酮戊二酸脱氢酶系中E1酶的基因kgd1,构建α-酮戊二酸脱氢酶活性缺失菌株T.glabratakgd1::kan,并考察KGDH缺失引起TCA循环关键酶活性,碳代谢流量以及胞内氨基酸和能荷水平等方面的变化。【结果】光滑球拟酵母中α-酮戊二酸脱氢酶活性的缺失导致:(1)细胞启动乙醛酸途径,通过形成TCA-乙醛酸循环实现TCA循环的正常代谢;(2)胞内NADH/NAD+水平下降33.7%,ATP/ADP水平下降31.8%,而与NADH代谢相关的丙酮酸脱氢酶、异柠檬酸脱氢酶和苹果酸脱氢酶的活性分别提高58.1%、33.3%和32.5%;(3)胞内丙酮酸含量下降50.1%,而胞内琥珀酸、苹果酸和α-酮戊二酸含量则分别增加了172.7%、66.1%和41.1%;(4)丙酮酸族氨基酸含量下降29.3%,而胞内谷氨酸族氨基酸和天冬氨酸族氨基酸含量则提高了34.7%和26.8%。【结论】上述研究结果表明,α-酮戊二酸脱氢酶系在微生物细胞中心碳代谢、能量代谢和氨基酸代谢中发挥着重要作用。[Objective] We studied the physiological function of α-ketoglutarate dehydrogenase complex （KGDH） on the metabolism of Torulopsis glabrata. [ Methods] With manipulation of KGDH in Torulopsis glabrata, we screened a mutant strain T. glabrata kgdl ： ： kan, in which the kgd1 gene encoding the E1 subunit of KGDH was deleted. [ Results] Disruption of KGDH resulted in： （a） the enhancement of glyoxalate pathway as a complementarity for carbon metabolism in TCA cycle; （b） compared with that of the control, the ratio of NADH/NAD ＋ and ATP/ADP decreased by 33.7% and 31.8% , respectively. But the specific activities of pyruvate dehydrogenase, isocitrate dehydrogenase and malate dehydrogenase increased by 58.1% , 33.3% and 32.5%, respectively; （c） the intracellular concentration of pyruvate was reduced by 49.9%, while the intracellular concentration of succinate, malate and α-ketoglutarate was higher 172.7%, 66.1% and 41.1% than the corresponding values of the control; （d） The content of pyruvate-family amino acid was 29.3% lower while the level of glutamate-family amino acid and aspartate-family amino acid were 34.7% and 26.8% higher than that of control. [ Conclusions] Those results present here demonstrated that α-ketoglutarate dehydrogenase complex plays essential role on the metabolism of yeast.

关 键 词：α-酮戊二酸脱氢酶系 光滑球拟酵母 Α-酮戊二酸 丙酮酸 

分 类 号：Q93[生物学—微生物学]