Plasma Membrane-stimulated Vanadate-dependent NADH Oxidation Is Not the Primary Mediator of Vanadate Toxicity in Succharomyces

Interactions of oxyvanadium compounds with cellular metabolism have recently been demonstrated. Membrane-stimulated vanadate-dependent NADH oxidation has been hypothesized to involve the cellular accumulation of HzOz, which may cause the vanadate sensitivity of animals and microbes. This report shows that the vanadate-dependent NADH oxidation activity of the yeast plasma membrane requires oxygen and is present in vanadate-resistant mutants of Saccharomyces cerevisiae. In addition, the vanadate sensitivity of growth in S. cerevisiae is the same during aerobic and anaerobic growth. These results imply that neither plasma membrane-mediated vanadate-stimulated NADH oxidation, nor any other oxidative process, is the primary cause of vanadate sensitivity in yeast cells.