B. Keita et al., CATALYSIS OF THE OXIDATION OF NADH BY HETEROPOLYANIONS - A KINETIC-STUDY, COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II FASCICULE C-CHIMIE, 1(5-6), 1998, pp. 343-350
The oxidation of NADH is readily obtained in the presence of Dawson-ty
pe heteropolyanions (HPA). A stoichiometry of 2:1 is established for t
he oxometalate/NADH couple. The starting system for electrochemistry s
tudies consists of the one-electron reduction product of the heteropol
yanions in the presence of various amounts of NADH. The quantitative s
tudy by cyclic voltammetry confirms that the oxidized form of the sele
cted HPAs are capable of catalyzing the oxidation of NADH. The kinetic
s were studied quantitatively by double-step chronocoulometry. The log
arithm of the second-order rate constant varies linearly with the E-0
of the first redox system of the HPAs with a slope of 16.4 V-1, indica
ting that the oxidation of NADH proceeds by a multistep mechanism invo
lving an initial rate-limiting one-electron transfer. The E degrees va
lue for the NADH/NADH(.+) redox couple has been estimated. (C) Academi
e des Sciences/Elsevier, Paris.