文献类型：会议

作　　者：Peng Wang,Ao Wang,Guo-Ping Zhu(Institute of Molecular Biology and Biotechnology,Anhui Normal University,Wuhu 241000)

作者单位：安徽师范大学分子生物学及生物技术研究所

会议文献：第四届全国微生物资源学术暨国家微生物资源平台运行服务研讨会论文集

会议名称：第四届全国微生物资源学术暨国家微生物资源平台运行服务研讨会

会议日期：20121126

会议地点：中国四川成都

主办单位：中国微生物学会微生物资源专业委员会

出版日期：20121200

学会名称：中国微生物学会微生物资源专业委员会

语　　种：中文

摘　　要：Isocitrate dehydrogenase(IDH) is one of the key enzymes in tricarboxylic acid cycle,widely distributed in Archaea,Bacteria and Eukarya.Here,we report for the first time the cloning,expression and characterization of a monomeric NADP+-dependent IDH from Streptomyces diastaticus No.7 strain M1033(SdIDH).Molecular mass of SdIDH was about 80 kDa and showed high amino acid sequence identity with known monomeric IDHs.Maximal activity of SdIDH was observed at pH 8.0(Mn2+) and 9.0(Mg2+),and the optimal temperature was 40°C(Mn2+) and 37°C(Mg2+).Heat-inactivation studies showed that SdIDH remained about 50% activity after 20 min of incubation at 47°C.SdIDH displayed a 19,000-fold and 32,000-fold(kcat/Km) preference for NADP+ over NAD+ with Mn2+ and Mg2+,respectively.Our work implicate that SdIDH is a divalent metal ion-dependent monomeric IDH with remarkably high coenzyme preference for NADP+.This work may provide fundamental information for further investigation on the catalytic mechanism of monomeric IDH and give a clue to disclose the real cause of IDH monomerization.

关 键 词：isocitrate dehydrogenase  enzymatic characterization  KINETICS coenzyme specificity  Streptomyces diastaticus  

分 类 号：Q93]