Merck, 23479-1KT-F, Nitrite/Nitrate Assay Kit, colorimetric

Application
Nitric oxide (NO), a gaseous paramagnetic radical, is a very important and versatile messenger in biological systems. NO is synthesized from L-arginine by NO synthase (NOS). It has been identified as an endothelial derived relaxation factor (EDRF) and antiplatelet substance. It serves as a neurotransmitter derived from a neutrophile and a cytotoxic substance from an activated macrophage. Although NO′s molecular action in the biological system is very versatile, the most important role of NO is the activation of guanylate cyclase.

The Griess assay is one of the most popular and simplest methods used to detect the NO concentration. The Griess assay′s mechanism is summarized as the azo coupling between diazonium species, which are produced from sulfanilamide with NO₂, and naphthylethylenediamine. The NO₂/NO₃ Assay Kit contains these dyes, a nitrate reductase, an enzyme co-factor, buffer solution and NO₂, NO₃ solutions as standards. Therefore, total NO metabolites are easily detectable using this kit. The suitable NO₂ detection range is from 10 to 100 μM.