Abstract
1. Formation of ATP coupled with nitrate respiration was confirmed in the sonic extract of Pseudomonas denitrificans.
2. P/2e ratio of 0.25 in the nitrate respiration was obtained with succinate as the electron donor. Lower P/2e ratio was obtained with other electron donors such as NADH, lactate, and formate.
3. Influence of various conditions of reaction, namely tonicity of the reaction medium and the concentration of Mg++, ADP, and P, on the nitrate respiration and coupled phosphorylation was studied.
4. Apparent apyrase activity was observed in the present bacterial preparation. The dephosphorylating activity was found to show a similar tendency of changes to the phos-phorylating activity on various conditions of the reaction medium.
5. In several preparations, the respiratory control was observed both in the nitrate respiration and in the oxygen respiration.
6. Some discussion on the phosphorylation coupled with bacterial respiration was presented on the basis of known mechanism of mitochondrial phosphorylation in the mammalian tissues.
The author wishes to express her sincere gratitude to Prof. T. Mori for his instruction and discussions throughout the work. The author also thanks to Prof. B. Hagihara of Osaka University for his valuable advices and discussions. Thanks are also due to Dr. T. Ohnishi of Nagoya University for his coworks, and to Mr. E. Itagaki of Osaka Univer-sity who helped the author in experiments by Cary spectrophotometer.
