Abstract
Thiamine-binding substances were found in 23 plant foodstuffs such as wheat germ, corn, buckwheat, sesame, radish, green tea, etc. They appeared to be two kinds of substances; one is heatlabile and pronase-sensitive, and the other is heat-stable and pronase-resistant. It would be inferred that the former is protein and the latter is non-protein compound. The binding of thiamine to thiamine-binding proteins was hardly inhibited by thiamine pyrophosphate, oxythiamine and pyrithiamine suggesting that the binding is specific to thiamine.
Furthermore, the thiamine-binding activity in buckwheat seed gradually decreased during 5 days' germination and disappeared over 90 per cent of the initial activity on the 5th day. These metabolic changes in thiamine-binding protein may be involved in the germination of buckwheat seed.
