Vanadium metabolism in wild type and respiratory-deficient strains of S. cerevisiae

Vanadium metabolism was studied in a wild type and respiratory-deficient strain of S. cerevisiae. Inhibition of growth by vanadate [V(+5)], vanadate accumulation, and conversion of medium vanadate [V(+5)] to both cell-associated and medium vanadyl [V(+4)] and vanadate [V(+5)] were compared. The growth of both the parental and respiratory-deficient strains was inhibited by vanadate at concentrations greater than or equal to 1 mM. Both parental and respiratory-deficient strains accumulated vanadate and converted medium vanadate to cellular vanadyl as detected using electron spin resonance (ESR). The accumulation of cell-associated vanadyl was correlated with the loss of medium vanadate in both strains using a chemical assay. In contrast, the respiratory-deficient strain showed a greater amount of a cell-associated vanadate compound, as detected with vanadium-51 nuclear magnetic resonance (51V-NMR), than the wild type strain or a representative respiratory-competent vanadate-resistant mutant. These data imply that mitochondrial function may be directly involved in vanadium metabolism.