Topic
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.
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TL;DR: Culture filtrates of Lactobacillus lactis and LactOBacillus bulgaricus were observed to contain material inhibitory against Staphylococcus aureus, and the inhibitory factor was identified as hydrogen peroxide.
213 citations
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TL;DR: It is demonstrated that NO possesses properties which protect against ROS toxicity and how the use of different NO donor compounds can lead to different conclusions about the role that NO can play in the cytotoxicity of ROS is demonstrated.
213 citations
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TL;DR: It was found that the kinetics of cobalt leaching is controlled by surface chemical reaction at temperatures lower than 45°C, however, diffusion through the product layer at temperatures higher than45°C controls the rate of cobALT leaching.
213 citations
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TL;DR: The increased commitment to catalysis observed for all mutants suggests that active-site hydration is important in the uncoupling to form hydrogen peroxide at the second branch point, as expected if the two-electron-reduced dioxygen-bound intermediate is not directly participating in the substrate activation step.
Abstract: The pathway for utilization of pyridine nucleotide derived reducing equivalents in the cytochrome P-450 monooxygenase systems has three major branch points. The first is a partitioning between autoxidation of a ferrous, oxygenated heme adduct and input of the second reducing equivalent required for monooxygenase stoichiometry. The second is between dioxygen bond scission and release of two-electron-reduced O2 as hydrogen peroxide. The third is between substrate hydrogen abstraction initiated by a putative higher valent iron-oxo species and reduction of this intermediate by two additional electrons to produce water in an overall oxidase stoichiometry. For all substrates investigated, the direct release of superoxide at the first branch point never competes with second electron input. In order to elucidate the aspects of molecular recognition of a substrate-P-450 complex which affect these individual branch points in the catalytic cycle, we have measured the NADH-derived reducing equivalents recovered in hydroxylated substrate, hydrogen peroxide, and water for a series of active-site mutants designed to alter the coupling of ethylbenzene hydroxylation. We find that the reaction specificity at the second and third branch points is affected by site-directed mutations that alter the topology of the binding pocket. The increased commitment to catalysis observed for all mutants suggests that active-site hydration is important in the uncoupling to form hydrogen peroxide at the second branch point. The liberation of hydrogen peroxide does not correlate with the location of the mutation in the pocket, as expected if the two-electron-reduced dioxygen-bound intermediate is not directly participating in the substrate activation step.(ABSTRACT TRUNCATED AT 250 WORDS)
212 citations
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TL;DR: It is suggested that resveratrol has the potential to prevent oxidative stress-induced cell death in cultured rat pheochromocytoma cells.
Abstract: Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities. One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), one of the major antioxidative constituents found in the skin of grapes, has been considered to be responsible in part for the protective effects of red wine consumption against coronary heart disease ('French Pardox'). In this study, we have investigated the effects of resveratrol on hydrogen peroxide-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with hydrogen peroxide underwent apoptotic death as determined by characteristic morphological features, internucleosomal DNA fragmentation and positive in situ end-labeling by terminal transferase (TUNEL staining). Resveratrol pretreatment attenuated hydrogen peroxide-induced cytotoxicity, DNA fragmentation, and intracellular accumulation of ROS. Hydrogen peroxide transiently induced activation of NF-kappaB in PC12 cells, which was mitigated by resveratrol pretreatment. These results suggest that resveratrol has the potential to prevent oxidative stress-induced cell death.
212 citations