GLUCOSE DEHYDROGENASE (HEXOSE 6-PHOSPHATE DEHYDROGENASE) AND THE MICROSOMAL ELECTRON-TRANSPORT SYSTEM - EVIDENCE SUPPORTING THEIR POSSIBLE FUNCTIONAL RELATIONSHIP

被引:28
作者
KIMURA, K
ENDOU, H
SUDO, J
SAKAI, F
机构
[1] Department of Pharmacology, Faculty of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113, Hongo
关键词
D O I
10.1093/oxfordjournals.jbchem.a132336
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The ability of a microsomal enzyme, glucose dehydrogenase (hexose 6-phosphate dehydrogenease) to supply NADPH to the microsomal electron transport system, was investigated. Microsomes could perform oxidative demethylation of aminopyrine using microsomal glucose dehydrogenase in situ as an NADPH generator. This demethylation reaction had apparent Km values of 2·6l×10-5 for NADP+ 4·93×10-5 for glucose 6-phosphate, and 2·14×10-4 M for 2-deoxyglucose 6-phosphate, a synthetic substrate for glucose dehydrogenase. Phenobarbital treatment enhanced this demethylation activity more markedly than glucose dehydrogenase activity itself. Latent activity of glucose dehydrogenase in intact microsomes could be detected by using inhibitors of microsomal electron transport, i.e. carbon monoxide and p-chloromercuribenzoate (PCMB), and under anaerobic conditions. These observations indicate that in microsomes the NADPH generated by glucose dehydrogenase is immediately oxidized by NADPH-cytochrome c reductase, and that glucose dehydrogenase may be functioning to supply NADPH. © 1979 By The Journal Of Biochemistry.
引用
收藏
页码:319 / 326
页数:8
相关论文
共 25 条