Oxidative phosphorylation coupled with anaerobic nitrate reduction was found to occur in cell-free extracts of Escherichia coli. The P/NO₃^- ratios during the reduction of nitrate to nitrite were 0.65 and 1.1 with glutamate and citrate, respectively, as electron donors. Phosphorylation coupled with nitrate reduction was inhibited in the presence of KCN and 2, 4-dinitrophenol but not in the presence of CO. Antimycin A and amytal acted as uncouplers of phosphorylation cou-pled with nitrate reduction.
The authors wish to express their thanks to the Public Health Research Institute of Kobe City, Kobe for its generosity in providing the strain of E. coli used here.