A 'branched' mechanism of the reverse reaction of yeast glutathione reductase. An estimation of the enzyme standard potential values from the steady-state kinetics data.
The reduced glutathione-linked NADP+ reduction, catalyzed by yeast glutathione reductase, follows a 'sequential' or 'ping-pong' mechanism at high or low NADP+ concentrations, respectively. The pattern of the NADPH and NADP+ cross-inhibition reflects not only the competition for the binding site, but the shift of the reaction equilibrium as well. A 'branched' scheme of the glutathione reductase reaction is presented. The enzyme standard potential (-255 mV, pH 7.0) was estimated from the ratio of the NADPH and NADP+ rate constants corresponding to the ping-pong mechanism.
Rakauskiene
G A
GA
Institute of Biochemistry, Academy of Sciences Lithuanian SSR, Mokslininku, USSR.
Cenas
N K
NK
Kulys
J J
JJ
D001667:Binding, Competitive; D005980:Glutathione Reductase / Q000378:metabolism*; D007700:Kinetics; D008962:Models, Theoretical; D009249:NADP; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D009249:NADP; D005980:Glutathione Reductase