Abstract
This paper deals with the action of O-benzoylthiamine disulfide (BTDS), a new thiamine lipotrophic derivative, on yeast. BTDS, in spite of its excellent vitamin activity on animal, exerted an inhibitory action at the early phase of incubation and then only a slight vitamin effect at the latter part of the logarithmic period in the growth experiment, using Saccharomyces cerevisiae 7753. In the fermentation test for thiamine assay of Schultz et al., BTDS required a longer induction period than most of other new thiamine derivatives for exhibition of the vitamin effect. To elucidate the course of the change of BTDS to thiamine, the forms of thiamine analogues in the supernatant and the yeast cell fractions were studied by paper chromatography after incubation of BTDS with yeast cell for 1 and 5 hours at 30℃. The compounds detected in each fractions were as follows : BTDS, in the supernatant of the incubation mixture ; OBT, in the supernatant and aqueous extract of the cell homogenate ; thiamine, in the aqueous extract, acid extract and pepsin digest of the yeast cell. From these results it will be considered that BTDS is transformed to OBT in the liquid phase and OBT is adsorbed to the surface of the cell wall and absorbed into the inner part of the cell as thiamine after cleavage of the benzoyl group.
