Abstract
It was demonstrated that thiamine, when added to the serine medium with the inoculation of serine-adapted Saccharomyces carlsbergensis 4228,was accumulated on the yeast cells to the extent over 2% of the cell weight, and the accumulation was markedly inhibited by phenylthiazinothiamine (PTT). Growth-inhibition of the yeast by addition of thiamine was not observed in the medium containing thiamine and PTT. When the cells, highly accumulated with thiamine, was inoculated in the medium containing serine and no thiamine, the yeast showed retarded growth. The rate of phosphorylation of thiamine in the fast-growing cells was shown to be higher than that in the delayed ones during the growth of both the original strain and its serine-adapted strain. These findings suggest that the thiamine abundantly accumulated in the yeast cells, plays an important role in the growth-inhibition of the yeast, and thiamine diphosphate in the yeast cells seems to stimulate the growth rather than inhibition.
