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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
Author(s) -
Rakauskien≐ Gelm≐ A.,
Č≐nas Narimantas K.,
Kulys Juozas J.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81212-8
Subject(s) - glutathione reductase , glutathione , chemistry , yeast , reductase , kinetics , enzyme , reaction rate constant , biochemistry , enzyme kinetics , reaction mechanism , stereochemistry , catalysis , active site , glutathione peroxidase , physics , quantum mechanics
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.