Chemical repair of protein carbon-centred radicals: long-distance dynamic factors

Castañeda‐Arriaga, Romina; Domínguez-Castro, Adrián; Lee, JinGyu; Álvarez-Idaboy, J. Raúl; Mora‐Diez, Nelaine

doi:10.1139/cjc-2016-0230

Cited by 7 publications

(12 citation statements)

References 53 publications

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“…This model requires the calculation of the steady-state Smoluchowski rate constant for an irreversible diffusion-controlled bimolecular reaction [ 32 ], and the application of the Stokes–Einstein approach [ 33 , 34 ]. Details on this methodology and the equations used can be found in previous publications [ 35 , 36 , 37 , 38 , 39 ]. This methodology has been successfully used in studies of primary and secondary antioxidant activity [ 22 , 23 , 24 , 35 , 36 , 37 , 38 , 39 , 40 ].…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical Study of the Iron Complexes with Aminoguanidine: Investigating Secondary Antioxidant Activity

García-Díez

Mora‐Diez

2020

Antioxidants

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A thorough analysis of the thermodynamic stability of various complexes of aminoguanidine (AG) with Fe(III) at a physiological pH is presented. Moreover, the secondary antioxidant activity of AG is studied with respect to its kinetic role in the Fe(III) reduction to Fe(II) when reacting with the superoxide radical anion or ascorbate. Calculations are performed at the M05(SMD)/6-311+G(d,p) level of theory. Solvent effects (water) are taken into account in both geometry optimizations and frequency calculations employing the SMD solvation method. Even though the results of this study show that AG can form an extensive number of stable complexes with Fe(III), none of these can reduce the rate constant of the initial step of the Haber–Weiss cycle when the reducing agent is O2•−. However, when the reductant is the ascorbate anion, AG is capable of reducing the rate constant of this reaction significantly, to the point of inhibiting the production of •OH radicals. In fact, the most stable complex of Fe(III) with AG, having a ∆Gf° of −37.9 kcal/mol, can reduce the rate constant of this reaction by 7.9 × 105 times. Thus, AG possesses secondary antioxidant activity relative to the Fe(III)/Fe(II) reduction with ascorbate, but not with O2•−. Similar results have also been found for AG relative to the Cu(II)/Cu(I) reduction, in agreement with experimental results.

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Section: Computational Detailsmentioning

confidence: 99%

Theoretical Study of the Iron Complexes with Aminoguanidine: Investigating Secondary Antioxidant Activity

García-Díez

Mora‐Diez

2020

Antioxidants

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“…The SMD model, which is based on the quantum mechanical charge density of the solute interacting with a continuum description of the solvent, is considered a universal solvation model, due to its applicability to any charged or uncharged solute in any solvent or liquid medium for which a few key descriptors are known [36]. The M06 and M06-2X functionals (or their previous versions, the M05 and M05-2X functionals) combined with the SMD continuum solvation model have been successfully used in various kinetic studies in solution [10][11][12][13][14][15][25][26][27][28].…”

Section: Computational Detailsmentioning

confidence: 99%

“…More detailed information on these expressions and their application in various studies can be found elsewhere [10][11][12][13][14][15]45].…”

Section: Computational Detailsmentioning

confidence: 99%

“…The M06 coordination distances from the Cu(II) central ion to the organic ligand are slightly shorter than in the M06-2X study in most cases, and they become shorter in the corresponding Cu(I) complex. Thermodynamic calculations related to the formation of the Cu(II)-DHLA 2− complexes at physiological pH, as shown in Equation (14), are reported in Table 6. The most stable Cu(II)-LAcomplex (reported as {1} in Reference 10; now labelled {9B}) was also recalculated, and its Cu(I) reduction product was optimized, {10B}.…”

Section: Copper (Ii) Complexes and Their Comparison With Fe(iii) Compmentioning

confidence: 99%

“…In this second approach, the ligand acts as a sacrifice target preventing • OH radicals from reacting with more important biomolecules such as lipids, proteins and DNA [6][7][8]. Theoretical approaches allow the kinetic study of various type of antioxidants [9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Study of the Iron Complexes with Lipoic and Dihydrolipoic Acids: Exploring Secondary Antioxidant Activity

et al. 2020

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The thermodynamic stability of twenty-nine Fe(III) complexes with various deprotonated forms of lipoic (LA) and dihydrolipoic (DHLA) acids, with coordination numbers 4, 5 and 6, is studied at the M06(SMD)/6-31++G(d,p) level of theory in water under physiological pH conditions at 298.15 K. Even though the complexes with LA- are more stable than those with DHLA−, the most thermodynamically stable Fe(III) complexes involve DHLA2−. The twenty-four exergonic complexes are used to evaluate the secondary antioxidant activity of DHLA and LA relative to the Fe(III)/Fe(II) reduction by O2•− and ascorbate. Rate constants for the single-electron transfer (SET) reactions are calculated. The thermodynamic stability of the Fe(III) complexes does not fully correlate with the rate constant of their SET reactions, but more exergonic complexes usually exhibit smaller SET rate constants. Some Cu(II) complexes and their reduction to Cu(I) are also studied at the same level of theory for comparison. The Fe(III) complexes appear to be more stable than their Cu(II) counterparts. Relative to the Fe(III)/Fe(II) reduction with ascorbate, DHLA can fully inhibit the formation of •OH radicals, but not by reaction with O2•−. Relative to the Cu(II)/Cu(I) reduction with ascorbate, the effects of DHLA are moderate/high, and with O2•− they are minor. LA has minor to negligible inhibition effects in all the cases considered.

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A density functional theory study of the free‐radical scavenging activity of aminoguanidine. Comparison with its reactive carbonyl compound and metal scavenging activities

Ramis

Casasnovas

Marino

et al. 2019

Int J of Quantum Chemistry

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Since protein glycation is related to several human diseases, it is very important to develop molecules that can inhibit its effects. This work adds the reaction of Aminoguanidine (AG) with the methoxy (˙OCH 3 ) and hydroperoxyl (˙OOH) radicals at the UM05-2X-SMD/6-311+G(d,p) level of theory in water and pentyl ethanoate to simulate the physiological aqueous and lipidic environments. At physiological pH, AG is an effective˙OCH 3 and a moderate˙OOH scavenger in nonpolar solvents (where AG is predominantly neutral), acting exclusively by hydrogen-atom transfer. However, reactions in a polar solvent (where AG is predominantly cationic) have smaller rate constants. Therefore, the ability of AG to scavenge free radicals seems to depend on the polarity of the environment. Taken together, the results reported herein and in previous works suggest that the scavenging of reactive carbonyl species is the main mechanism of action of aminoguanidine in the context of protein glycation inhibition. K E Y W O R D S aminoguanidine, glycation, inhibition, RCS and metal scavenging, ROS

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Chemical repair of protein carbon-centred radicals: long-distance dynamic factors

Cited by 7 publications

References 53 publications

Theoretical Study of the Iron Complexes with Aminoguanidine: Investigating Secondary Antioxidant Activity

Theoretical Study of the Iron Complexes with Aminoguanidine: Investigating Secondary Antioxidant Activity

Theoretical Study of the Iron Complexes with Lipoic and Dihydrolipoic Acids: Exploring Secondary Antioxidant Activity

A density functional theory study of the free‐radical scavenging activity of aminoguanidine. Comparison with its reactive carbonyl compound and metal scavenging activities

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