Amplite? Fluorimetric Extracellular Nitric Oxide (NO) Activity Assay Kit. Nitric oxide (NO) is an important biological regulator involved in numbers of physiological and pathological processes. Altered NO production is implicated in various immunological, cardiovascular, neurodegenerative and inflammatory diseases. As a free radical, NO is rapidly oxidized and there is relatively low concentrations of NO existing in biological systems. It has been challenging to detect and understand the role of NO using conventional tools. AAT Bioquest offers a group of NO assay kits for monitoring NO in live cells. This Amplite? Extracellular Fluorimetric Nitric Oxide Quantitation Kit provides a rapid method to monitor NO level in extracellular media, tissues, and other biological solutions and samples. Compared to the commonly used DAF-2 probe, DAW-J2 is used as the cell-impermeant NO sensor in our kit 16365. DAW-J2 detects nitric oxide exclusively in the extracellular environment with high sensitivity and selectivity. The non-fluorescent DAW-J2 probe reacts with NO to generate a strongly red fluorescent product that can be conveniently monitored using a microplate reader at Ex/Em = 570/610 nm.