THE METABOLISM OF YEAST SPORULATION. VI. CHANGES IN AMINO ACID CONTENT DURING SPOROGENESIS.

Abstract

During 6-day exposures of cells of Saccharomyces cerevisiae to acetate sporulation medium, the content of free amino acids declined to approximately one-third of that of vegetative cells, but proline was exceptional in that it increased conspicuously in amount. The content of combined amino acids also diminished to about one-third, ammonia was evolved, and amino acids (not including proline) passed out of the cells into the medium. When dihydroxyacetone replaced acetate in the sporulation medium, the results were similar except that the decline in content of free and combined amino acids was much greater, more ammonia was evolved, and only very small amounts of amino acids could be detected in the medium. Transfer of sporulated cells to growth medium led to an increase in the pool of free amino acids, except for proline, which declined in amount.In two other species of Saccharomyces the free proline content also increased on exposure to sporulation medium, but in Schizosaccharomyces pombe and Torulopsis famata no such increase was observed.