Nitric oxide synthases (EC 220.127.116.11) (NOS) is a family of enzymes that catalyze the production of nitric oxide (NO). In presence of NADPH, FAD, FMN, (6R)-5,6,7,8-tetrahydrobiopterin, calmodulin and heme, NOS catalyzes a five-electron oxidation of the guanidino nitrogen of L-arginine with molecular oxygen to generate NO and L-citrulline. Nitric oxide plays an important role in neurotransmission, vascular regulation, immune response and apoptosis. In contrast to its beneficial effects, NO has also been associated with numerous pathological situations such as hypotension accompanying septic shock, essential hypertension, and atherosclerosis. The overproduction of NO has been found to be the fundamental cause underlying neurodegenerative disorders and neuropathic pain. Therefore, developing small molecules for inhibition of NOS is therapeutically desirable. LSBio's Nitric Oxide Synthase Inhibitor Screening Kit provides a simple and high-throughput adaptable method to screen/study/characterize potential NOS inhibitors. In this assay, nitric oxide generated by NOS undergoes a series of reactions and reacts with the fluorescent probe to generate a stable signal at Ex/Em = 360/450 nm, which is directly proportional to NOS activity. In the presence of a NOS-specific inhibitor, the formation of NO is reduced/abolished resulting in decrease or total loss of the fluorescence.