'This study describes a simple, reliable, highly sensitive and quantitative fluorescence microplate-assay of H2O2 from activated leukocytes using a novel horse radish peroxidase (HRP) substrate N-acetyl-3,7-dihydroxyphenoxazine (A6550). Unlike the widely used fluorescent HRP substrate scopoletin, A6550 is non-fluorescent and becomes highly fluorescent upon HRP-catalyzed H2O2 oxidation. Using 50 microM A6550, ... More
H2O2 is required for UVB-induced EGF receptor and downstream signaling pathway activation.
AuthorsPeus D, Meves A, Vasa RA, Beyerle A, O'Brien T, Pittelkow MR
JournalFree Radic Biol Med
PubMed ID10641711
Ultraviolet radiation (UVR)-induced receptor phosphorylation is increasingly recognized as a widely occurring phenomenon. However, the mechanisms, mediators, and sequence of events involved in this process remain ill-defined. We have recently shown that exposure of human keratinocytes to physiologic doses of ultraviolet B radiation (UVB) activates epidermal growth factor receptor (EGFR)/extracellular-regulated ... More
NADPH oxidase activation increases the sensitivity of intracellular Ca2+ stores to inositol 1,4,5-trisphosphate in human endothelial cells.
Many stimuli that activate the vascular NADPH oxidase generate reactive oxygen species and increase intracellular Ca(2+), but whether NADPH oxidase activation directly affects Ca(2+) signaling is unknown. NADPH stimulated the production of superoxide anion and H(2)O(2) in human aortic endothelial cells that was inhibited by the NADPH oxidase inhibitor diphenyleneiodonium ... More
A stable nonfluorescent derivative of resorufin for the fluorometric determination of trace hydrogen peroxide: applications in detecting the activity of phagocyte NADPH oxidase and other oxidases.
AuthorsZhou M, Diwu Z, Panchuk-Voloshina N, Haugland RP
JournalAnal Biochem
PubMed ID9367498
The enzymatic determination of hydrogen peroxide can be accomplished with high sensitivity and specificity using N-acetyl-3, 7-dihydroxyphenoxazine (Amplex Red), a highly sensitive and chemically stable fluorogenic probe for the enzymatic determination of H2O2. Enzyme-catalyzed oxidation of Amplex Red, which is a colorless and nonfluorescent derivative of dihydroresorufin, produces highly fluorescent ... More
Hydrogen peroxide formation during iron deposition in horse spleen ferritin using O2 as an oxidant.
AuthorsLindsay S, Brosnahan D, Watt GD
JournalBiochemistry
PubMed ID11258954
The reaction of Fe2+ with O2 in the presence of horse spleen ferritin (HoSF) results in deposition of FeOH3 into the hollow interior of HoSF. This reaction was examined at low Fe2+/HoSF ratios (5-100) under saturating air at pH 6.5-8.0 to determine if H2O2 is a product of the iron ... More