Efficient depletion of ascorbate by amino acid and protein radicals under oxidative stress

Domazou, Anastasia S.; Zelenay, Viviane; Koppenol, Willem H.; Gebicki, Janusz M.

doi:10.1016/j.freeradbiomed.2012.08.005

Cited by 14 publications

(11 citation statements)

References 46 publications

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“…The rst way is that part of the radical groups on membrane surface could transfer to protein to form protein free radicals. 29,30 The protein free radicals react with radical groups on membrane surface and protein is graed on membrane surface because of coupling termination. The second way is that the unreacted amine groups on collagen molecules react with the carbonyl groups on membrane surface and collagen molecule is introduced on the surface of membrane.…”

Section: Resultsmentioning

confidence: 99%

Surface modification of a PVDF membrane by cross-linked collagen

Sun

Tong

2014

RSC Adv.

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A polyvinylidene fluoride (PVDF) membrane was modified by a low temperature plasma treatment and grafted with cross-linked collagen. The crosslinker of collagen was glutaraldehyde. The effects of glutaraldehyde concentration, crosslinking time and crosslinking temperature on membrane properties and surface structure were investigated. The properties of the modified membrane were characterized by the contact angle and pure water flux. The surface structure of the membrane dyed with an acid dye was observed by a polarizing microscope. The modified membrane was further characterized concerning permeability and adsorption capacity. Bovine serum albumin (BSA) was used as a model protein. The cell culture ability of the membrane was examined by the methyl thiazolyl tetrazolium (MTT) method. The amount of grafted collagen on the membrane surface reached the maximum when collagen was cross-linked with 0.4 wt% glutaraldehyde for 1 h at 35 C. The BSA adsorption capacity and cell culture ability examination indicated that the PVDF membrane grafted with cross-linked collagen had good hydrophilicity and biocompatibility.

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Section: Resultsmentioning

confidence: 99%

Surface modification of a PVDF membrane by cross-linked collagen

Sun

Tong

2014

RSC Adv.

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“…The resultant new estimates of the plausible concentrations of polyphenols and their aromatic metabolites in vivo allow an approximate evaluation of their ability to scavenge C-centered protein radicals in competition with oxygen. Assuming the upper limit of [O 2 ] at 13 μM in cells [ 17 ] and rate constants of adduct formation between Pr ● and polyphenols and their aromatic metabolites of 5 × 10 9 M −1 s −1 [ 73 ], with k = 2.4 × 10 9 M −1 s −1 for the reaction (amino acid) ● + O 2 [ 99 ], 50% scavenging of the Protein ● in competition with Reaction (3) requires a 6.2 μM concentration of the aromatic antioxidants. Such levels of sustained concentrations should be easily achievable in vivo from a diet rich in vegetable content and may be sufficient to tip the balance from oxidative stress to antioxidant protection [ 75 , 92 , 93 ].…”

Section: Repair Of Protein Radicalsmentioning

confidence: 99%

Initiation and Prevention of Biological Damage by Radiation-Generated Protein Radicals

Gebicki

Nauser

2021

IJMS

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Ionizing radiations cause chemical damage to proteins. In aerobic aqueous solutions, the damage is commonly mediated by the hydroxyl free radicals generated from water, resulting in formation of protein radicals. Protein damage is especially significant in biological systems, because proteins are the most abundant targets of the radiation-generated radicals, the hydroxyl radical-protein reaction is fast, and the damage usually results in loss of their biological function. Under physiological conditions, proteins are initially oxidized to carbon-centered radicals, which can propagate the damage to other molecules. The most effective endogenous antioxidants, ascorbate, GSH, and urate, are unable to prevent all of the damage under the common condition of oxidative stress. In a promising development, recent work demonstrates the potential of polyphenols, their metabolites, and other aromatic compounds to repair protein radicals by the fast formation of less damaging radical adducts, thus potentially preventing the formation of a cascade of new reactive species.

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“…The question now is how these radicals will disappear. This problem can be elucidated by examining the experiments and kinetic analysis of Domazou et al [ 39 ]. Thus, a protein radical cannot disappear by a reaction with another component, such as another protein, since the ‘old’ radical will disappear but a new radical will be born.…”

Section: Postscript: Radical Metabolismmentioning

confidence: 99%

“…There could be a way to repair POOH back to an intact protein, but this is not the main point being made here. According to these authors [ 39 ], reactions of ascorbate with radicals such as P∙ and POO∙ may account for the depletion of ascorbate observed during oxidative stress. Fortunately, in many cases ascorbate competes with oxygen for P∙ and P∙ will be converted back to the intact protein.…”

Section: Postscript: Radical Metabolismmentioning

confidence: 99%

Free Radicals: How Do We Stand Them? Anaerobic and Aerobic Free Radical (Chain) Reactions Involved in the Use of Fluorogenic Probes and in Biological Systems

Liochev¹

2013

Med Princ Pract

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Biologically significant conclusions have been based on the use of fluorogenic and luminogenic probes for the detection of reactive species. The basic mechanisms of the processes involved have not been satisfactorily elucidated. In the present work, the mechanism of the enzyme and photosensitized oxidation of NAD(P)H by resorufin is analyzed and appears to involve both aerobic and anaerobic free radical chain reactions. There are two major fallouts of this analysis. Many of the conclusions about the participation of radicals based on the use of probes such as resorufin and Amplex red need reevaluation. It is also concluded that anaerobic free radical reactions may be biologically significant, and the possible existence of enzymatic systems to eliminate certain free radicals is discussed.

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Efficient depletion of ascorbate by amino acid and protein radicals under oxidative stress

Cited by 14 publications

References 46 publications

Surface modification of a PVDF membrane by cross-linked collagen

Surface modification of a PVDF membrane by cross-linked collagen

Initiation and Prevention of Biological Damage by Radiation-Generated Protein Radicals

Free Radicals: How Do We Stand Them? Anaerobic and Aerobic Free Radical (Chain) Reactions Involved in the Use of Fluorogenic Probes and in Biological Systems

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