Hydrogen peroxide

About: Hydrogen peroxide is a research topic. Over the lifetime, 42583 publications have been published within this topic receiving 1043732 citations. The topic is also known as: H2O2 & dioxidane.

Reduced stress defense in heme oxygenase 1-deficient cells

Abstract: Stressed mammalian cells up-regulate heme oxygenase 1 (Hmox1; EC 1.14.99.3), which catabolizes heme to biliverdin, carbon monoxide, and free iron. To assess the potential role of Hmox1 in cellular antioxidant defense, we analyzed the responses of cells from mice lacking functional Hmox1 to oxidative challenges. Cultured Hmox1−/− embryonic fibroblasts demonstrated high oxygen free radical production when exposed to hemin, hydrogen peroxide, paraquat, or cadmium chloride, and they were hypersensitive to cytotoxicity caused by hemin and hydrogen peroxide. Furthermore, young adult Hmox1−/− mice were vulnerable to mortality and hepatic necrosis when challenged with endotoxin. Our in vitro and in vivo results provide genetic evidence that up-regulation of Hmox1 serves as an adaptive mechanism to protect cells from oxidative damage during stress.

Heme oxygenase is the major 32-kDa stress protein induced in human skin fibroblasts by UVA radiation, hydrogen peroxide, and sodium arsenite.

Abstract: We have shown that UVA (320-380 nm) radiation, hydrogen peroxide, and sodium arsenite induce a stress protein of approximately 32 kDa in human skin fibroblasts. The synthesis and cloning of cDNA from arsenite-induced mRNA populations have now allowed us to unequivocally identify the 32-kDa protein as heme oxygenase. By mRNA analysis we have shown that the heme oxygenase gene is also induced in cultured human skin fibroblasts by UVA radiation, hydrogen peroxide, cadmium chloride, iodoacetamide, and menadione. The known antioxidant properties of heme catabolites taken together with the observation of a high level of induction of the enzyme in cells from an organ not involved in hemoglobin breakdown strongly supports the proposal that the induction of heme oxygenase may be a general response to oxidant stress and constitutes an important cellular defense mechanism against oxidative damage.

Photocatalytic degradation of azo dye acid red 14 in water on ZnO as an alternative catalyst to TiO2

Abstract: The degradation of acid red 14 (AR14), commonly used as a textile dye, can be photocatalysed by ZnO. Using advanced oxidation processes (AOPs), zinc oxide appears to be a suitable alternative to TiO2 for water treatment. In this study, a detailed investigation of photocatalytic degradation of acid red 14 is presented. Photodegradation efficiency was small when the photolysis was carried out in the absence of ZnO and it was also negligible in the absence of UV light. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction (K=0.0548 min−1). The effects of some parameters such as pH, amount of photocatalyst, hydrogen peroxide and ethanol concentration were also examined. The addition of proper amount of hydrogen peroxide improved the decolorization, while the excess hydrogen peroxide could quenched the formation of hydroxyl radicals ( OH). As our results indicated that ethanol inhibited the photodegradation of dye, we concluded from the inhibitive effect of ethanol that hydroxyl radicals played a significant role in the photodegradation of dye. This should not undermine direct oxidation caused by positive holes.