Hydrogen peroxide (H2O2) is an important member of the reactive oxygen species (ROS) family. Among ROS, H2O2 is considered the most long-lived and can accumulate inside and outside of cells, where it is involved in both vital (signaling) and deadly (toxic) reactions depending on its concentration. Quantifying H2O2 within biological samples is challenging and often not possible. Here we present ...

objective: it is well-known that all living cells emit ultra-weak photon emission (upe), which is due to byproducts of chemical reactions in cell metabolisms. it has been shown that reactive oxygen species (ros) in the cells enhances the upe intensity. the magnitude of such upe is extremely weak (i.e. a few to 103 photons/ (sec.cm2)), and the detection of such ultra-weak signals is hardly possi...

The concentration of hydrogen peroxide (H2O2) in exhaled air has been reported to be elevated in asthma and chronic obstructive pulmonary disease (COPD), but results are inconsistent and difficult to reproduce. As H2O2 occurs in ambient air, we examined its association with exhaled H2O2 in human subjects. Exhaled breath condensate (EBC) of 12 COPD patients and nine healthy control subjects was ...

Thimet oligopeptidase (EC 3.4.24.15, TOP) is a cytosolic mammalian zinc protease that can process a diversity of bioactive peptides. TOP has been pointed out as one of the main postproteasomal enzymes that process peptide antigens in the MHC class I presentation route. In the present study, we describe a fine regulation of TOP activity by hydrogen peroxide (H2O2). Cells from a human embryonic k...

BACKGROUND In this research, the removal of natural organic matter from aqueous solutions using advanced oxidation processes (UV/H2O2) was evaluated. Therefore, the response surface methodology and Box-Behnken design matrix were employed to design the experiments and to determine the optimal conditions. The effects of various parameters such as initial concentration of H2O2 (100-180 mg/L), pH (...

OBJECTIVE We tested the hypotheses that low concentration of H2O2 attenuates the Ca2+ paradox (Ca2+ PD) injury, and that activation of protein kinase C (PKC) and/or ATP-sensitive potassium channel (KATP) are involved in the protective effects of H2O2. METHODS Langendorff-perfused rat hearts were subjected to the Ca2+ PD (10 min of Ca2+ depletion followed by 10 min of Ca2+ repletion). Function...

Generation of H2O2 by rat liver mitochondria with choline, glycerol 1-phosphate and proline as substrates has been shown by using high-concentration phosphate buffer. Rates obtained under these conditions were higher and more consistent as compared with the earlier reports with high-concentration mannitol/sucrose/Tris buffer. Sulphate ions could replace phosphate indicating a requirement for a ...