Nitric Oxide Synthase Activity Typed Assay kit

Nitric oxide synthase (NOS, EC 1.14.13.39, written as total NOS (TNOS) after) is a type of enzyme that catalyzes the synthesis of NO from L-arginine in living organisms. It mainly exists invarious cells such as vascular smooth muscle, macrophages, endothelial cells, neurons, liver cells, and glomerularmesangial cells. According to the different dependence of its enzyme activity on calciumions, it can be divided into structural NOS (constructive NOS, cNOS) and injury induced NOS (inducible NOS, iNOS).The former requires a certain concentration of calcium ions to activate, while the latter does not relyonexogenous calcium ions. NOS catalyzes L-arginine, molecular oxygen and NADPH to form NO and NADP+. NO is easily oxidized to form NO2- and NO3- in aqueous solution. Under acidic conditions, NO2- and diazoniumsulfonamide produce diazo compounds. The compounds could further couple with naphthyl vinyl diamine. The product has a characteristic absorption peak at 550 nm and its absorbance value can be measured to calculate NOS activity.