Abstract
1. Mitochondria prepared from aerated mycelia of Aspergillus oryzae in 0.5M sucrose containing 0.01M EDTA catalyzed the phosphorylation coupled with oxidation of succinate.
2. The phosphorylative activity was stabilized by addition of K-citrate.
3. High concentration of iP and hexokinase in the reaction mixture increased the phosphorylative activity. Addition of iP increased oxidation but hexokinase did not.
4. The oxidative phosphorylation had two pH optima at pH 6.3 and 7.0.
5. Addition of a nucleotide complex prepared from the organism and of DPN stimulated oxidative phosphorylation (as judged by the P/O ratio).
6. The inhibitory effect of antimycin A and 2, 4-DNP was studied. Antimycin A-insensitive oxidation of this preparation was very small and the phosphorylation mechanism, is tightly coupled with oxidation.
The author wishes to express his thanks to Prof. K. Okunuki for his valuable guidance. Thanks are also due to his colleagues Mr. T. Higashiyama of the same laboratory, and Dr. F. Imamoto of the laboratory of pharmacology, faculty of medicine, Osaka University, for their help and discussion.
