The effect of pantothenate on sulfate metabolism and sulfur isotope fractionation by Saccharomyces cerevisiae.

Growth of Saccharomyces cerevisiae in minimal salts-glucose-SO4(2-) medium with varying concentrations of pantothenate (0-1000 microgram/L) produced changes in the cellular lipid content and in the ratio of saturated to unsaturated fatty acids. Substantial differences in SO4(2-) diffusion were also observed with changes in pantothenate concentration. During sulfate reduction, the delta 34S value of the evolved sulfide varied with the pantothenate concentration ranging from -31% in the absence of pantothenate to 0% at 400-1000 microgram/L pantothenate. The isotope selectivity is related to the effect of pantothenate concentration on cellular metabolism.