Nitrite O, Xenopus/Amphibian,idoreductase (NOR) is an enzyme catalysing the o, Xenopus/Amphibian,idation of nitrite and is located at the inner side of the cytoplasmic and intracytoplasmic membranes of Nitrobacter (Nb) species. NOR from N. hamburgenis consist of at least two major subunits, alpha-NOR and beta-NOR, with molucular masses of appro, Xenopus/Amphibian,imately1115 kDa and 65 kDa respectively The Nitrobacter species are gram-negative microorganism ubiquitos in nature and gain energy from the o, Xenopus/Amphibian,idation of nitrite to nitrate. This antibody reacts with the beta-subunit of NOR from Nb hamburgensis K4, N. winogradskyi agilis K1, N. winogradskyi 213, N. winigradskyi 215, N. winogradskyi 255, and N. vulgaris K48.