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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01 Jan 1991
TL;DR: Aconitase was purified over 135fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria.
Abstract: Preincubation of potato (Solanum tuberosum) tuber mitochondria with 300 microM-H2O2 for 10 min nearly stopped the State 3 rate of citrate oxidation. Addition of isocitrate resulted in resumption of O2 uptake. The State 3 rates of succinate, external NADH and 2-oxoglutarate oxidation were unaffected by H2O2 over the dose range 50-500 microM. Preincubation of mitochondria with 300 microM-H2O2 for 5 min unmasked in the matrix space a paramagnetic signal with a peak at a g value of approx. 2.03. Aconitase was purified over 135-fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria. The native enzyme was composed of a single polypeptide chain (molecular mass 90 kDa). Incubation of purified aconitase with small amounts of H2O2 caused the build up of a paramagnetic 3Fe cluster with a low-field maximum of g = 2.03 leading to a progressive inhibition of aconitase activity. The results show that aconitase present in the matrix space was the major intramitochondrial target for inactivation by H2O2.
173 citations
TL;DR: The enzyme horseradish peroxidase has been entrapped in situ by electropolymerization of pyrrole onto a platinum electrode and the biosensor retained more than 90% of its original activity after 35 days of use.
173 citations
TL;DR: The production of single strand cleavage in covalently-closed circular-DNA by the antitumour agent streptonigrin (reduced in situ by NADH) is demonstrated using the ethidium bromide fluorescence assay described previously.
Abstract: The production of single strand cleavage in covalently-closed circular-DNA by the antitumour agent streptonigrin (reduced in situ by NADH) is demonstrated using the ethidium bromide fluorescence assay described previously. The degradation dependent on oxygen is completely inhibited by superoxide dismutase (EC 1.15.1.1) suggesting the intermediacy of the superoxide radical anion in the degradation. However similar complete inhibition of DNA strand breakage by catalase (EC 1.11.1.6) indicates that the hydroxyl radical (formed by interaction of superoxide with hydrogen peroxide) is the primary reactive species. Cupric ion stimulates the cleavage reaction and cobaltous ion has no effect in keeping with model studies using quinolinequinones.
173 citations
TL;DR: In this paper, the authors investigated the catalytic systems for the direct production of hydrogen peroxide from hydrogen and oxygen, and the factors which make a successful process identified, such as low metal loadings, an organic co-solvent (such as ethanol) and reduced palladium as catalytic metal all lead to good activity and selectivity.
Abstract: Catalytic systems for the direct production of hydrogen peroxide from hydrogen and oxygen are investigated, and the factors which make a successful process identified. The use of low metal loadings, an organic co-solvent (such as ethanol) and reduced palladium as the catalytic metal all lead to good activity and selectivity.
173 citations
TL;DR: In this paper, a nano-composite film consisting of amine functionalized graphene and gold nanoparticles (AuNPs) modified glassy carbon electrode was used for direct electrochemistry and electrocatalysis of catalase.
172 citations