The analogous mechanisms of enzymatic inactivation induced by ascorbate and superoxide in the presence of copper.

Shinar, Eilat; Navok, T; Chevion, Mordechai

doi:10.1016/s0021-9258(17)43728-8

Cited by 152 publications

(9 citation statements)

References 32 publications

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“…Reducing equivalents may serve as both pro oxidants and anti-oxidant compounds. For example, it has been shown that ascorbic acid may react with transition metals such as copper or iron to produce the highly reactive hydroxyl radical (Shinar et al, 1983;Higson et al, 1988). Therefore, following CHI or postischemia, high levels of reducing equivalents may act as pro-oxidants rather than anti-oxidants, while interacting with the redox-active metals, re leased within the damaged area.…”

Section: Discussionmentioning

confidence: 99%

Changes of Biological Reducing Activity in Rat Brain following Closed Head Injury: A Cyclic Voltammetry Study in Normal and Heat-Acclimated Rats

Beit‐Yannai

Kohen

Horowitz

et al. 1997

J Cereb Blood Flow Metab

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Reactive oxygen species (ROS) are normally generated in the brain during metabolism, and their production is enhanced by various insults. Low molecular weight antioxidants (LMWA) are one of the defense mechanisms of the living cell against ROS. The reducing capacity of brain tissue (total LMWA) was measured by cyclic voltammetry (CV), which records biological oxidation potential specific to the type of scavenger(s) present and anodic current intensity (Ia), which depends on scavenger concentration. In the present study, the reducing capacity of rat brain following closed head injury (CHI) was measured. In addition, CV of heat-acclimated traumatized rats was used to correlate endogenous cerebroprotection after CHI with LMWA activity. Sham-injured rat brains displayed two anodic potentials: at 350 +/- 50 mV (Ia = 0.75 +/- 0.06 microA/mg protein) and at 750 +/- 50 mV (Ia = 1.00 +/- 0.05 microA/mg protein). Following CHI, the anodic waves appeared at the same potentials as in the sham animals. However, within 5 min of CHI, the total reducing capacity was transiently decreased by 40% (p < 0.01). A second dip was detected at 24 h (60%, p < 0.005). By 48 h and at 7 days, the Ia levels normalized. The acclimated rats displayed anodic potentials identical to those of normothermic rats. However, the Ia of both potentials was lower (60% of control, p < 0.001). The Ia profile after CHI was the direct opposite of the normothermic Ia profile: no immediate decrease of Ia and an increase from 4 h and up to 7 days (40-50%, p < 0.001). We suggest that the lowered levels of LMWA in the post-CHI period reflect their consumption due to overproduction of free radicals. The augmented concentration of LMWA found in the brain of the heat-acclimated rats suggests that these rats are better able to cope with these harmful radicals, resulting in a more favorable outcome following CHI.

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Section: Discussionmentioning

confidence: 99%

Changes of Biological Reducing Activity in Rat Brain following Closed Head Injury: A Cyclic Voltammetry Study in Normal and Heat-Acclimated Rats

Beit‐Yannai

Kohen

Horowitz

et al. 1997

J Cereb Blood Flow Metab

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“…It is accompanied by the one-electron reduction of molecular oxygen with the reduced metal ion yielding oxygen-derived free radical species (Khan and Martell, 1967a,b). The metal/ascorbate system enhances the oxidation of various food and biological materials including proteins (Samuni et al, 1983; Shinhar et al, 1983; Marx and Chevion, 1985), which directly results in the fragmentation of protein and the oxidative modification of amino acid residues (Uchida and Kawakishi, 1988). In addition, metal-catalyzed protein oxidations have been recently implicated to be important causative agents of oxygen toxicity in aging and its related deseases (Oliver et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Sequence-dependent reactivity of histidine-containing peptides with copper(II)/ascorbate

Uchida¹,

Kawakishi²

1992

J. Agric. Food Chem.

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“…In vitro, a metal/ascorbate system promotes the oxidative scission of various food and biological materials such as polysaccharides (Uchida and Kawakishi, 1986a), proteins (Samuni et al, 1983;Shinar et al, 1983;Levine, 1984;Marx and Chevion, 1985; Uchida and Kawakishi, 1988), and DNA (Chiou, 1983(Chiou, ,1984. Especially on reaction with protein, this system gives rise to the specific modification of the histidine residues in the protein (Levine, 1984;Marx and Chevion, 1985;Uchida and Kawakishi, 1988).…”

mentioning

confidence: 99%

Ascorbate-mediated specific modification of histidine-containing peptides

Uchida¹,

Kawakishi²

1989

J. Agric. Food Chem.

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The analogous mechanisms of enzymatic inactivation induced by ascorbate and superoxide in the presence of copper.

Cited by 152 publications

References 32 publications

Changes of Biological Reducing Activity in Rat Brain following Closed Head Injury: A Cyclic Voltammetry Study in Normal and Heat-Acclimated Rats

Changes of Biological Reducing Activity in Rat Brain following Closed Head Injury: A Cyclic Voltammetry Study in Normal and Heat-Acclimated Rats

Sequence-dependent reactivity of histidine-containing peptides with copper(II)/ascorbate

Ascorbate-mediated specific modification of histidine-containing peptides

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