A novel dimeric oxovanadium (IV) species identified in Saccharomyces cerevisiae cells.

Saccharomyces cerevisiae cells stored oxovanadium (IV) ions in a dimeric form. In the late stationary phase Saccharomyces cerevisiae cells grown in rich medium containing concentrations of oxovanadium (V), orthovanadate from 12 to 18 mM, causing growth stasis, a dimeric oxovanadium (IV) species was identified by EPR spectroscopy. The EPR spectrum exhibited at 110 K the low-field forbidden deltaMs = +/-2 transition at g around 4 and the half-field deltaMs = +/-1 15-lines feature at g around 2 out of the presence of a triplet state by the coupling of the oxovanadium (IV) ions in a dimeric form. Hyperfine splitting of 75.2 x 10(-4) cm(-1) and an interionic distance of about 4.4 angstroms was calculated. The dimeric species was localized in the cellular cytoplasmic space.