Abstract
1. Using Atkin-Schultz-Frey's microbiological assay for thiamine based on the accelerating effect of thiamine on yeast fermentation, the effect of thiamine and of 24 derivatives on anaerobic decarboxylation was examined.
2. This method can be applied as a biological test of thiamine derivatives, if it is taken into consideration that the action on yeast is not always in agreement with that on animals.
3. Following thiamine derivatives were examined; (a) S, S-alkyl derivatives show the accelerating effect as much as, or a little more than, thiamine. (b) Of O, S-diacyl thiamines, O, S-diacetyl thiamine is as active as thiamine and the effects of other compounds appeared in the following decreasing order.
O, S-Diacetyl>dipropionyl>S-propionyl-O-benzoyl>dibenzoyl. Once the effects have appeared, they were all as active as thiamine. (c) O-Acyl derivatives were somewhat inferior to thiamine. (d) S-Alkyl derivatives have generally little activity, if any. (e) Thiothiamines have no activity. (f) As antivitamins, hydroxythiamine, butylthiamine and heteropyrithiamine were examined, of which hydroxythiamine alone showed a slight antithiamine activity.
4. As for the mechanism of accelerating effect, the relation to nirogen metabolism is important, and the effect of nitrogen sources, increase in nitrogen in cells and promotion of budding were observed. Further, participation of metal ions and the permeability of cell membrane were observed.
