Abstract
Reduction of nitrate to nitrite by washed cell suspension of Cl. welchii was studied by coupling this reaction with dehydrogenation of glucose or ethyl alcohol and also with hydrogenase. The experimental results of the effects of various inhibitors on nitrate reducing activity of the organism, including those of addition of nitrate to culture medium, led to the conclusion that the nitrate reducing activity of Cl. welchii cells depended on the presence of nitrate reductase, participating in activation of nitrate molecule, distinct from dehydrogenases or hydrogenase themselves. Some properties of the nitrate reductase of Cl. welchii was studied, especially in comparison with those of E. coli.
The authors wish to express their sincere thanks to Prof. Seigo Hosoya and Dr. Shonosuke Miyasaki for their kind help for this study. They also express their thanks to Mr. Shusuke Hirano for his assistance.
