【摘要】 对嗜热乙醇杆菌中的醇脱氢酶E(alcohol dehydrogenase E,AdhE)进行了克隆、表达和鉴定,证明先前报道的醛脱氢酶其实是AdhE。对AdhE在乙醇代谢中的功能与调控进行了研究。通过分析测定AdhE的酶学性质、AdhE在嗜热乙醇杆菌的不同生长时期的表达情况以及AdhE高表达时嗜热乙醇杆菌产乙醇/乙酸的比率变化,证明了AdhE的主要生理功能是促使乙醇产生。分析了嗜热乙醇杆菌在山梨糖(强还原性碳源)、葡萄糖(氧化还原性居中的碳源)和葡糖醛酸(强氧化性碳源)诱导培养下的AdhE表达量,证明氧化还原力是AdhE的表达调控信号之一。更多还原

【Abstract】 An alcohol dehydrogenase(AdhE) gene(adhE) from Thermoanaerobacter ethanolicus was cloned and identified in Escherichia coli.The results indicated that the acetaldehyde dehydrogenase reported previously was AdhE.To probe the function of AdhE,the recombinant AdhE was characterized,and the expression of AdhE in different growth stage of T.ethanolicus was analyzed.These data show that the AdhE is optimized for ethanol formation and not its consumption.The regulation of the adhE gene was investigated by the accumulation of reducing equivalents.When sugar alcohols such as sorbitol were used as carbon sources,the adhE expression was obviously increased compared with expression when glucose was the carbon sources,whereas when oxidized sugar derivatives such as gluconate were used,the expression was limitedly increased.The NADH/NAD ratio was suggested to be a signal for regulation of adhE.更多还原