Biochemical studies on sulfate-reducing bacteria. XV. Separation and comparison of two forms of desulfoviridin

Desulfoviridin from Desulfovibrio vulgaris was separated into two forms by DEAE-Sephadex column chromatography. The major form had a pI of 4.4 and the minor form one of 4.5-4.6. Both forms produced mainly trithionate, besides thiosulfate and sulfide, in methylviologen-linked sulfite reduction. The specific activities of sulfite reduction, as well as of hydroxylamine reduction, were virtually identical in both forms. There were no great differences in their absorption spectra, CD spectra, molecular weights, subunit compositions, labile sulfide, and iron contents, and amino acid compositions. The N-terminal amino acid was alanine in both forms.