Active Transport of Exogenous S -Adenosylmethionine and Related Compounds into Cells and Vacuoles of Saccharomyces cerevisiae

Abstract

Saccharomyces cerevisiae 4094-B (α, ade-2, ura-1 ) in potassium phosphate buffer with glucose under aerobic conditions took up (−) S -adenosyl- l -methionine from the medium in sufficient quantity to permit the demonstration of its accumulation in the vacuole by ultraviolet micrography. The same result was obtained with (±) S -adenosyl- l -methionine, (±) S -adenosyl- d -methionine, and (−) S -adenosyl- l -ethionine. The rate of uptake was slow with (−) S -adenosyl- S ( n -propyl)- l -homocysteine and S -adenosyl- d -homocysteine. S -Adenosyl- l -homocysteine was assimilated rapidly, but intracellular degradation precluded accumulation and ultraviolet micrographic studies. The uptake of 5′-methyl-, 5′-ethyl-, 5′- n -propylthioadenosine, and 5′-dimethylsulfonium adenosine was minimal.