Reactions of nitric oxide and peroxynitrite with organic molecules and ferrihorseradish peroxidase: Interference with the determination of hydrogen peroxide

摘要: Abstract Endothelial, inflammatory, and other cell types, in addition to forming reactive oxygen species, under proper stimulation release free radicals such as nitric oxide ('NO) strong oxidants peroxynitrite (ONOO-), which is the product of reaction with superoxide. Several methods for detection H2O2 are based on ferrihorseradish peroxidase catalyzed oxidation organic molecules. We investigated reactions molecules well examined potential interference H2O2. Peroxynitrite at low concentrations (010 μM) induced a concentration-dependent 1,2 phenylenediamine, 3-3′ dimethoxybenzidine (odianisidine) para-hydroxyphenylacetic acid (pHPA). With exception pHPA, above compounds by was not affected presence peroxidase. The yield HPA-dimmer, pHPA peroxynitrite, decreased because formation different product, 3-nitro-HPA. Nitrogen oxides, formed oxygen, oxidized aromatic amines o-phenylenediamine o-dianisidine. A 10-fold excess over dihydrorhodamine 123 (DHR123) 58 72%, respectively, compared plus inhibition due part compound I II phenoxyl radical. These data suggest that simultaneous generation can interfere overestimation or underestimation detected dependent upon molecule utilized relative rate oxide, superoxide, generation.