The oxidation of NADH by vanadate plus sugars.

Sugars and sugar phosphates enable vanadate to catalyze the oxidation of NADH. Superoxide dismutase inhibits this oxidation. Incubation of sugars with vanadate, prior to addition of NADH, accelerates this oxidation of subsequently added NADH and eliminates the lag phase otherwise noted. Incubation of sugars with vanadate also results in the reduction of vanadate to vanadyl, with appearance of a blue-green color probably associated with a vanadyl-vanadate complex. It appears that sugars reduce vanadate to vanadyl which, in turn, reduces O2 to O2- and that vanadate plus O2- then catalyzes the oxidation of NAD(P)H by a free radical chain reaction. Such oxidation of NAD(P)H may account for several of the biological effects of vanadate.