Effect of biotin-sparing substances on growth of biotindeficient Saccharomyces cerewisiae and on the synthesis of nucleic acids and protein

A11 examination was made of the ability of amino acids, purines and related compounds, and fatty acids to stimulate growth of Sncchmrornyces cerevisiae in biotin-deficient medium and to restore the synthesis of nucleic acids and protein. Adenine, adenosine. aspartic acid and Cas-amino 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 tha t brought about by the other biotin-sparing compounds tested and i t was not accompanied by a restoration of nucleic acid and protein synthesis. Stimu-lation 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