Is involved in NO detoxification in an aerobic process, termed nitric oxide dioxygenase (NOD) reaction that utilizes O(2) and NAD(P)H to convert NO to nitrate, which protects the cell from various noxious nitrogen compounds. Therefore, plays a central role in the inducible response to nitrosative stress. In the presence of oxygen and NADH, it has NADH oxidase activity, which leads to the generation of superoxide and H(2)O(2). Under anaerobic conditions, it also exhibits nitric oxide reductase and FAD reductase activities. However, all these reactions are much lower than NOD activity (By similarity). NADPH + 2 nitric oxide + 2 O2 = H(+) + NADP(+) + 2 nitrate NADH + 2 nitric oxide + 2 O2 = H(+) + NAD(+) + 2 nitrate Binds 1 FAD per subunit. Binds 1 heme b group per subunit. Accumulates in macrocysts. By submerged conditions, in growing cells. Consists of two distinct domains; a N-terminal heme-containing oxygen-binding domain and a C-terminal reductase domain with binding sites for FAD and NAD(P)H. Belongs to the globin family. Two-domain flavohemoproteins subfamily. In the C-terminal section; belongs to the flavoprotein pyridine nucleotide cytochrome reductase family.