Biochemical Characterization and Complete Conversion of Coenzyme Specificity of Isocitrate Dehydrogenase from Bifidobacterium longum.
Biochemical Characterization and Complete Conversion of Coenzyme Specificity of Isocitrate Dehydrogenase from Bifidobacterium longum.
复制标题
长双歧杆菌异柠檬酸脱氢酶的生化表征和辅酶特异性的完全转换。
DOI：
10.3390/ijms17030296
复制
发表时间：
2016-02-26
影响因子：
5.6
通讯作者：
Zhu GP
中科院分区：
文献类型：
--
作者：
Huang SP;Cheng HM;Wang P;Zhu GP
Bifidobacterium longum is a very important gram-positive non-pathogenic bacterium in the human gastrointestinal tract for keeping the digestive and immune system healthy. Isocitrate dehydrogenase (IDH) from B. longum (BlIDH), a novel member in Type II subfamily, was overexpressed, purified and biochemically characterized in detail. The active form of BlIDH was an 83-kDa homodimer. Kinetic analysis showed BlIDH was a NADP+-dependent IDH (NADP-IDH), with a 567- and 193-fold preference for NADP+ over NAD+ in the presence of Mg2+ and Mn2+, respectively. The maximal activity for BlIDH occurred at 60 °C (with Mn2+) and 65 °C (with Mg2+), and pH 7.5 (with Mn2+) and pH 8.0 (with Mg2+). Heat-inactivation profiles revealed that BlIDH retained 50% of maximal activity after incubation at 45 °C for 20 min with either Mn2+ or Mg2+. Furthermore, the coenzyme specificity of BlIDH can be completely reversed from NADP+ to NAD+ by a factor of 2387 by replacing six residues. This current work, the first report on the coenzyme specificity conversion of Type II NADP-IDHs, would provide better insight into the evolution of NADP+ use by the IDH family.
