Thiamine diphosphate in growing tissues: IV. Pyruvate oxidation in muscle mitochondria from young rats and in mitochondria from malignant tissues

Abstract

In skeletal muscle mitochondria from adult rat about 75 per cent of their thiamine diphosphate content can be lost without impairment of the pyruvate oxidation capacity. Muscle mitochondria from newborn rats metabolize pyruvate very slowly as compared with muscle mitochondria from adult animals. Although they are very poor in thiamine diphosphate, addition of the cofactor does not significantly influence the oxidation rate. In mitochondria from spontaneous mammary carcinoma which have a thiamine diphosphate level comparable with that of muscle mitochondria from newborn rats, addition of thiamine diphosphate causes a small but distinct rise in the oxidation rate of pyruvate and α-ketoglutarate.