Nitric oxide (NO) plays an important role in neurotransmission, vascular regulation, immune response and apoptosis. Since NO is rapidly converted to nitrite (NO??) and nitrate (NO??), the total concentration of nitrite and nitrate is used as a quantitative measure of NO production. BioVision's Nitric Oxide Fluorometric Assay Kit provides an accurate and convenient measurement of total nitrate/nitrite concentration in a simple two-step process. In the first step nitrate is converted to nitrite by nitrate reductase. In the second step, nitrite reacts with the fluorescent probe DAN (2, 3 diaminonaphthalene). NaOH enhances the fluorescent yield. The fluorescent intensity is proportional to the total nitric oxide production. The kit has been tes