摘要
Objective:To investigate the effect of oxidized transitional metal（ferric and cupric） ions on the amino acids.Methods:25 mmol/L hydroxyproline and 25 mmol/L histidine were incubated with 50μL Fe<sup>3+</sup> and Cu<sup>2+</sup> ions at pH 7.4 and 37℃for 30 mins in separate test tubes.Then 500μL of 1% thiobarbituricacid（TBA） was added to the incubated amino acids followed by addition of 500μL of glacial acetic acid.The resultant mixture was vortexed and heated at 100℃for 30 min.Absorbance readings were noted after cooling to room temperature.The experiment was repeated in the presence of various reagents,like hydroxyl radical scavengers,antioxidant enzymes,and reducing agents and metal ion chelators.Results:The pink chromogen formed with the absorbance maxima at 524 nm,AND shifted to 560 nm in alkaline pH.The absorbance was expressed as TBAadduct in MDA units.The TBA-adduct decreased in the presence of reducing agents and metal ion chelators.Antioxidant enzymes and hydroxyl radical scavengers did not show any effect. Conclusion:Transitional metal ions in their oxidized state showed significant damage to amino acids,hydroxyproline and histidine.The results indicate the possible role played by high-valent oxo-iron species,ferryl and perferry radicals in damaging biomolecules.
Objective:To investigate the effect of oxidized transitional metal(ferric and cupric) ions on the amino acids.Methods:25 mmol/L hydroxyproline and 25 mmol/L histidine were incubated with 50μL Fe^(3+) and Cu^(2+) ions at pH 7.4 and 37℃for 30 mins in separate test tubes.Then 500μL of 1% thiobarbituricacid(TBA) was added to the incubated amino acids followed by addition of 500μL of glacial acetic acid.The resultant mixture was vortexed and heated at 100℃for 30 min.Absorbance readings were noted after cooling to room temperature.The experiment was repeated in the presence of various reagents,like hydroxyl radical scavengers,antioxidant enzymes,and reducing agents and metal ion chelators.Results:The pink chromogen formed with the absorbance maxima at 524 nm,AND shifted to 560 nm in alkaline pH.The absorbance was expressed as TBAadduct in MDA units.The TBA-adduct decreased in the presence of reducing agents and metal ion chelators.Antioxidant enzymes and hydroxyl radical scavengers did not show any effect. Conclusion:Transitional metal ions in their oxidized state showed significant damage to amino acids,hydroxyproline and histidine.The results indicate the possible role played by high-valent oxo-iron species,ferryl and perferry radicals in damaging biomolecules.
