Abstract
SUMMARY: An examination was made of the ability of amino acids, purines and related compounds, and fatty acids to stimulate growth of Saccharomyces cerevisiae in biotin-deficient medium and to restore the synthesis of nucleic acids and protein. Adenine, adenosine, aspartic acid and Casamino acids (Difco) each stimulated growth to some extent and brought about a partial restoration of nucleic acid and protein synthesis. Oleic acid also stimulated growth, but the effect was much slower than that brought about by the other biotin-sparing compounds tested and it was not accompanied by a restoration of nucleic acid and protein synthesis. Stimulation of growth in biotin-deficient media supplemented with aspartic acid + oleic acid was greater than the stimulation brought about by these compounds singly. During growth of the yeast in biotin-deficient media supplemented with this or certain other mixtures of biotin-sparing compounds there was a well defined exponential phase of growth which was not apparent during growth of the yeast in unsupplemented biotin-deficient medium. But the final cell crop in these supplemented media was still only about half of that obtained in biotin-optimal medium. These results are discussed in relation to the role of biotin in the synthesis of various yeast cell constituents.