Superoxide Dismutase AN ENZYMIC FUNCTION FOR ERYTHROCUPREIN (HEMOCUPREIN)
25 Nov 1969-Journal of Biological Chemistry (American Society for Biochemistry and Molecular Biology)-Vol. 244, Iss: 22, pp 6049-6055
TL;DR: The demonstration that O2·- can reduce ferricytochrome c and tetranitromethane, and that superoxide dismutase, by competing for the superoxide radicals, can markedly inhibit these reactions, is demonstrated.
About: This article is published in Journal of Biological Chemistry.The article was published on 1969-11-25 and is currently open access. It has received 12468 citations till now. The article focuses on the topics: Copper chaperone for superoxide dismutase & Superoxide reductase.
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TL;DR: Attention is focussed on the ROS/RNS-linked pathogenesis of cancer, cardiovascular disease, atherosclerosis, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, rheumatoid arthritis, and ageing.
12,240 citations
Cites background from "Superoxide Dismutase AN ENZYMIC FUN..."
...…radicals 46 M. Valko et al. / The International Journal of Biochemistry & Cell Biology 39 (2007) 44–84 of Bioc i e 1 h l g & d n b t f g ( a b b R e i a t O c t n e 2 i d o f r o e i t d b r a t o 4 A r f F b M. Valko et al. / The International Journal n living systems (McCord & Fridovich, 1969)....
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TL;DR: The staining procedure for localizing superoxide dismutase on polyacrylamide electrophoretograms has been applied to extracts obtained from a variety of sources and could thus be assayed either in crude extracts or in purified protein fractions.
10,933 citations
TL;DR: There is growing evidence that aging involves, in addition, progressive changes in free radical-mediated regulatory processes that result in altered gene expression.
Abstract: At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...
9,131 citations
TL;DR: The autoxidation of pyrogallol was investigated in the presence of EDTA in the pH range 7.9–10.6, indicating an almost total dependence on the participation of the superoxide anion radical, O2·−, in the reaction.
Abstract: The autoxidation of pyrogallol was investigated in the presence of EDTA in the pH range 7.9–10.6.
The rate of autoxidation increases with increasing pH. At pH 7.9 the reaction is inhibited to 99% by superoxide dismutase, indicating an almost total dependence on the participation of the superoxide anion radical, O2·−, in the reaction. Up to pH 9.1 the reaction is still inhibited to over 90% by superoxide dismutase, but at higher alkalinity, O2·− -independent mechanisms rapidly become dominant.
Catalase has no effect on the autoxidation but decreases the oxygen consumption by half, showing that H2O2 is the stable product of oxygen and that H2O2 is not involved in the autoxidation mechanism.
A simple and rapid method for the assay of superoxide dismutase is described, based on the ability of the enzyme to inhibit the autoxidation of pyrogallol.
A plausible explanation is given for the non-competitive part of the inhibition of catechol O-methyltransferase brought about by pyrogallol.
9,030 citations
TL;DR: Evidence that the appropriate and inappropriate production of oxidants, together with the ability of organisms to respond to oxidative stress, is intricately connected to ageing and life span is reviewed.
Abstract: Living in an oxygenated environment has required the evolution of effective cellular strategies to detect and detoxify metabolites of molecular oxygen known as reactive oxygen species. Here we review evidence that the appropriate and inappropriate production of oxidants, together with the ability of organisms to respond to oxidative stress, is intricately connected to ageing and life span.
8,665 citations
References
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TL;DR: The data are consistent with the conclusion that xanthine oxidase generates an unstable reduced form of oxygen, presumably the superoxide anion, and that this radical is the agent which directly reduces cytochrome c and initiates the sulfite-oxygen chain reaction.
1,163 citations
727 citations
TL;DR: The deflavoenzyme is catalytically active in the oxidation of xanthine with acceptors such as ferricyanide and cytochrome c.
233 citations
TL;DR: It has been found that peroxidase catalyzes the formation of free radicals of hydrogen donors in the presence of H 2 O 2, and Compound III is not an active intermediate for dihydroxyfumarate oxidation.
222 citations
TL;DR: It is concluded that the species observed is the superoxide ion, O(2) (-), and that the stability of this ion is greatly increased in alkaline solution.
Abstract: 1. An electron-spin-resonance signal with g( parallel)2.08 and g( perpendicular)2.00 is observed by the rapid-freezing technique during the oxidation of substrates by molecular oxygen catalysed by xanthine oxidase at pH10. 2. The intensity of this signal is shown to depend on oxygen rather than on enzyme concentration, indicating that it is due to an oxygen free radical and not to the enzyme. 3. The same species is shown to be produced in the reaction at pH10 between hydrogen peroxide and periodate ions. Studies with this system have facilitated comparison of the properties of the oxygen radical with data in the literature on the products of pulse radiolysis of oxygenated water over a wide pH range. 4. It is concluded that the species observed is the superoxide ion, O(2) (-), and that the stability of this ion is greatly increased in alkaline solution. A mechanism explaining the alkaline stability is proposed. 5. The importance of O(2) (-) in the enzymic reaction is discussed.
220 citations