一氧化氮合酶（ＮＯＳ）包括内皮细胞性、神经原性和诱生性三种，其基因分别位于人第７、１２和１７号染色体上。ＮＯＳ是高度保守性蛋白，种属间同一ＮＯＳ的氨基酸同源性大于８０％，但不同ＮＯＳ间仅５０％左右。业已证明ＮＯＳ是非均一性酶，同一酶可存在于不同细胞，而一种细胞可有一种以上的酶。ＮＯＳ的活性受基因转录、翻译、翻译后修饰等多环节调控。对ＮＯＳ的调控研究可指导ＮＯ介导的疾病进行针对性防治 Nitric oxide synthase (NOS), including endothelial cells, neurogenic and induced three, the gene located on chromosome 7, 12 and 17 respectively. NOS is a highly conserved protein. The amino acid identity of the same NOS among species is more than 80%, but only about 50% between different NOS. NOS has been shown to be a heterogeneous enzyme, the same enzyme can exist in different cells, and a cell can have more than one enzyme. NOS activity by gene transcription, translation, post-translational modification and other aspects of regulation. Regulation of NOS can guide the disease-mediated NO prevention and treatment