ＮＯ 是在ＮＯＳ的作用下，以Ｌ精氨酸和分子氧为底物，最终生成的。ＮＯ对细胞内信息的传递起着重要作用，同时又是杀伤肿瘤细胞的效应分子。ＮＯ 可以介导免疫细胞杀伤肿瘤细胞，而体内持续超量的ＮＯ，也可以引起基因突变和细胞癌变。ＮＯ 主要是与线粒体呼吸链上复合物中的ＦｅＳ基作用，形成ＦｅＳ亚硝酰基复合物，抑制呼吸链中电子的传递，从而引起细胞毒性。 NO is produced by L arginine and molecular oxygen as substrates under the action of NOS. NO plays an important role in the transmission of intracellular information, and it is also an effector molecule that kills tumor cells. NO can mediate the killing of tumor cells by immune cells, and the continuous excess of NO in the body can also cause gene mutation and cell canceration. NO mainly interacts with the FeS group in complexes on the mitochondrial respiratory chain to form FeS nitrosyl complexes, inhibiting electron transport in the respiratory chain and causing cytotoxicity.