Hydrogen Peroxide Colorimetric Detection Kit

In biological systems, incomplete reduction of O2 during respiration produces superoxide anion (O2-¬), which is spontaneously or enzymatically dismutated by superoxide dismutase to H2O2 . Many cells produce low levels of O2 -¬ and H2O2 in response to a variety of extracellular stimuli, such as cytokines (TGF-beta1, TNF-alpha, and various interleukins), peptide growth factors (PDGF, EGF, VEGF, bFGF, and insulin), the agonists of heterotrimeric G protein-coupled receptors (GPCR) such as angiotensin II, thrombin, lysophosphatidic acid, sphingosine 1-phosphate, histamine, and bradykinin, and by shear stress. The addition of exogenous H2O2 , or the intracellular production in response to receptor stimulation, affects the function of various proteins including protein kinases, protein phosphatases, transcription factors, phospholipases, ion channels, and G proteins. In 1894, Fenton described the oxidation of tartaric acid by Fe2+ and H2O2. H2O2 and O2 may participate in the production of singlet oxygen and peroxynitrite and the generation of these species may be concurrent with reactions involving iron, which under some circumstances might be important contributors to H2O2 toxicity.