DECREASE OF APOENZYME ACTIVITIES IN VITAMIN-DEFICIENT ANIMALS

I. DECREASE OF PYRUVATE-APOOXIDASE ACTIVITY IN VITAMIN B₁-DEFICIENT RATS

Abstract

1. The apoenzyme activities of pyruvate oxidase system in the liver of B₁-deficient rats were studied in vitro under various addition of DPT, CoA, lipoic acid, DPN, FAD, niacinamide, cytochrome c, ATP, glutathione, fumaric acid as well as pyridoxal-5-phosphate. A marked decrease of the apoenzyme activities in B₁-deficient rats were always demonstrated in the uptake of O₂ after adding pyruvate.
2. The apoenzyme activities of pyruvate oxidase system were recognized to be high in B₁-positive control rats fed a diminished caloric ration comparable to B₁-deficient groups.
3. The results seem to lead to the conclusion that thiamine contributes to the formation and activation of the apoenzyme in pyruvate oxidase system of rats as stated in the biochemical study on vitamin B₁₂.