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.
Papers published on a yearly basis
Papers
More filters
TL;DR: The model of an ortho substitution of hydroxyl groups to the aromatic ring seems to be adequate for antioxidant and H(2)O( 2) or DPPH(*) scavenging activity of phenolic acids.
835 citations
TL;DR: It was found that homocysteine plus copper could lyse the cells in a dose-dependent manner, an effect that was completely prevented by catalase, and these findings may be relevant to the mechanism of some types of chronic vascular injury.
Abstract: We have examined whether the toxic effects of homocysteine on cultured endothelial cells could result from the formation and action of hydrogen peroxide. In initial experiments with a cell-free system, micromolar amounts of copper were found to catalyze an oxygen-dependent oxidation of homocysteine. The molar ratio of homocysteine oxidized to oxygen consumed was approximately 4.0, which suggests that oxygen was reduced to water. The addition of catalase, however, decreased oxygen consumption by nearly one-half, which suggests that H2O2 was formed during the reaction. Confirming this hypothesis, H2O2 formation was detected using the horseradish peroxidase-dependent oxidation of fluorescent scopoletin. Ceruloplasmin was also found to catalyze oxidation of homocysteine and generation of H2O2 in molar amounts equivalent to copper sulfate. Finally, homocysteine oxidation was catalyzed by normal human serum in a concentration-dependent manner. Using cultured human and bovine endothelial cells, we found that homocysteine plus copper could lyse the cells in a dose-dependent manner, an effect that was completely prevented by catalase. Homocystine plus copper was not toxic to the cells. Specific injury to endothelial cells was seen only after 4 h of incubation with homocysteine plus copper. Confirming the biochemical studies, ceruloplasmin was also found to be equivalent to Cu++ in its ability to cause injury to endothelial cells in the presence of homocysteine. Since elevated levels of homocysteine have been implicated in premature development of atherosclerosis, these findings may be relevant to the mechanism of some types of chronic vascular injury.
834 citations
TL;DR: Iron metabolism, and its coupling with regulation of defenses against oxidative stress, as well as the role played by iron in regulatory protein in sensing redox change, appear as essential factors for life in the presence of oxygen.
833 citations
TL;DR: Positively-charged gold nanoparticles possess intrinsic peroxidase-like activity, and can catalyze oxidation of the per oxidase substrate 3,3,5,5-tetramethylbenzidine by H(2)O( 2) to develop a blue color in aqueous solution, thus providing a simple approach to colorimetric detection of H(1)O (2) and glucose.
824 citations
TL;DR: In this article, it was shown that acid red 14 (AR14) can be photocatalytically degraded using TiO 2 suspensions irradiated by a UV-C lamp (30 W).
Abstract: Acid Red 14 (AR14), commonly used as a textile dye, could be photocatalytically degraded using TiO 2 suspensions irradiated by a UV-C lamp (30 W). The experiments showed that TiO 2 and UV light had a negligible effect when they were used on their own. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction ( K =1.41×10 −2 min −1 ). The effects of some parameters such as pH, the amount of TiO 2 and initial dye concentration were also examined. The photodegradation of AR14 was enhanced by the addition of proper amount of hydrogen peroxide, but it was inhibited by ethanol. From the inhibitive effect of ethanol it was deducted that hydroxyl radicals played a significant role in the photodegradation of dye, but a direct oxidation by positive holes was probably not negligible. Accordingly, it could be stated that the complete removal of color, after selecting optimal operational parameters could be achieved in a relatively short time, about 3.5 h.
820 citations