Oxidative phosphorylation in liver mitochondria of the rat bearing Walker carcinoma 256.

Oxidation was found to be efficiently coupled with phosphorylation in the liver mitochondria of the rat bearing Walker carcinoma 256. With succinate as substrate, the rates of oxidation and phosphorylation by the liver mitochondria of the tumor-bearing rat did not differ from the normal. The P:O ratios were 1.4 for the normal and 1.2 for the tumor-bearing rats. With j8-hydroxybutyrate as substrate, the rates of oxidation and phosphorylation by the liver mitochondria of the tumor-bearing rat were significantly less than those for the normal rat. The P:0 ratios, however, did not differ, being 2.5 both for the normal and for the tumor-bearing rat. The addition of DPN brought the rates of oxidation and phosphorylation by the tumor-bearing rat nearly to normal. The P:O ratios in the presence of DPN and ßhydroxybutyrate were 1.6 for the normal and 1.4 for the tumor-bearing rat.