Abstract
Growth of an adenine-requiring yeast and a baker’s yeast was markedly inhibited by the addition of methionine to culture media. The inhibition was reversed by adenine or more clearly by adenine plus glucose supplements. The inhibition by methionine of the adenine-requiring yeast was more pronounced when the media contained relatively low levels of adenine. Further addition of adenine to the media reversed the inhibition. It appears, therefore, that methionine is a competitive inhibitor of adenine for growth of the yeast cells.