Effects of accumulated S-adenosylmethionine on growth of yeast cells

S-adenosylmethionine (SAM) accumulated in cultured yeast cells and affected growth in two ways. High levels of intracellular SAM in yeast inhibited early growth, but increased growth in medium without sources of nitrogen and sulfur. Accumulated SAM in the yeast cells was recycled as a nutritional source depending on the sulfur and nitrogen contents of the medium.