Kinetic properties of sheep brain glutathione reductase.
The kinetic properties of sheep brain glutathione reductase (GSSGR) were investigated. The enzyme showed Ping-Pong kinetics with double substrate inhibition in the forward direction. Km values for NADPH and GSSG were found to be 60.9 and 116.9 mumol/l, and Ki values were found to be 42.1 and 347.3 mumol/l, respectively. NADP+ inhibition at low fixed concentration of NADPH was mixed-type with a Ki of 281.5 mumol/l and alpha of 0.048. It is concluded that the enzyme shows a hybrid Ping-Pong-ordered branched mechanism.
Acan
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Department of Biochemistry, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Tezcan
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D000818:Animals; D001921:Brain / Q000201:enzymology*; D005978:Glutathione / Q000378:metabolism* / Q000494:pharmacology; D005980:Glutathione Reductase / Q000737:chemistry* / Q000187:drug effects; D007700:Kinetics; D009249:NADP / Q000378:metabolism / Q000494:pharmacology; D012756:Sheep
D009249:NADP; D005980:Glutathione Reductase; D005978:Glutathione