uNOS Polyclonal Antibody

Background/Target Information

Nitric oxide (NO) is an inorganic, gaseous free radical that carries a variety of messages between cells including vasorelaxation, neurotransmission and cytotoxicity. NOS catalyzes the oxidization of L-arginine to produce L-citrulline and NO. Two constitutive isoforms, brain/neuronal NOS (b or nNOS, type I) and endothelial cell NOS (eNOS, type III), and one inducible isoform (iNOS, type II), have been cloned. All isoforms contain calmodulin, NADPH, FAD, and FMN binding domains. iNOS is found in a variety of cell types including macrophages, hepatocytes, synoviocytes, and smooth muscle cells. Cytokines such as IFNg, TNF, IL-1, IL-2, and LPS cause an increase in iNOS mRNA, protein, and activity levels. After cytokine induction, iNOS exhibits a delayed activity response which is then followed by a significant increase in NO production over a long period of time. bNOS and eNOS share ~50% homology and their enzymatic activity depends on binding to the calcium/calmodulin complex. iNOS, however, is tightly bound to calmodulin and acts independently of calcium levels. Both constitutive isoforms respond immediately to increased levels of calcium to produce low levels of NO over a short time. In vascular endothelial cells NOS appears to modulate vasotension and platelet aggregation. bNOS is found in neurons, peripheral nerve cells, macula densa, and pancreatic islet cells.