ABSTRACT
Many bacteria can utilize nitrate as terminal hydrogen acceptor instead of oxygen. This process, called nitrate respiration or dissimilatory nitrate reduction, occurs only under anaerobic conditions. The first step of nitrate reduction is a reduction of nitrate to nitrite. The different methods that have been used for the solubilization of nitrate reductase from the cytoplasmic membrane during enzyme isolation procedure. The different procedures used for the solubilization of nitrate reductase have led to the isolation of different nitrate reductase complexes. It has been shown, for instance, that nitrate reductase from E. coli can be solubilized while still complexed with formate dehydrogenase. Two different approaches have been used to study the localization of nitrate reductase in cytoplasmic membranes. Nitrate reductase protein is labeled in situ or enzymic methods are employed for the localization of the active center of the enzyme.
