Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, 25030 Besançon, Cedex, France.
Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, 25030 Besançon, Cedex, France.
J Photochem Photobiol B. 2018 Nov;188:95-99. doi: 10.1016/j.jphotobiol.2018.09.009. Epub 2018 Sep 12.
The oxidation of proteins results in their deterioration via the oxidation of reactive amino acids. Oxidation of the amino acid, methionine plays an important role during biological conditions of oxidative stress, and equally a role in protein stability. In this study the oxidation of the methionine residue using the tripeptide GlyMetGly with respect to hydrogen peroxide has been studied using both Raman spectroscopy and DFT calculations. Spectral modifications following the formation of methionine sulfoxide are shown with the appearance of the SO vibration whilst there is also the modification of the CS vibrations at approximately 700 cm. The changes in the intensity of the CS stretching band were used to calculate the kinetic rate constant as 7.9 ± 0.6 × 10 dm mol s. The energy barrier for the reaction. is determined both experimentally and using DFT calculations. The reaction of the dairy protein beta-lactoglobulin with hydrogen peroxide is equally studied using the same technique. The solvent accessible surface area of the methionine residues within the protein were also determined and a comparison of the reaction rate constant and the energy barriers of reaction for the oxidation of the tripeptide and for the protein respectively thus, provides information about the role of the protein environment in the oxidation process.
蛋白质的氧化会导致其通过反应性氨基酸的氧化而劣化。在氧化应激的生物条件下，氨基酸蛋氨酸的氧化起着重要作用，同样在蛋白质稳定性中也起着重要作用。在这项研究中，使用三肽 GlyMetGly 研究了在过氧化氢存在下蛋氨酸残基的氧化，同时使用拉曼光谱和 DFT 计算进行了研究。形成蛋氨酸亚砜后，SO 振动的出现表明出现了光谱修饰，而 CS 振动也在大约 700 cm 处发生修饰。CS 伸缩带强度的变化用于计算动力学速率常数为 7.9±0.6×10dm mol s。使用 DFT 计算和实验确定了反应的能垒。同样使用相同的技术研究了乳蛋白 β-乳球蛋白与过氧化氢的反应。还确定了蛋白质中蛋氨酸残基的溶剂可及表面积，并比较了三肽和蛋白质的氧化反应的速率常数和反应能垒，从而提供了有关蛋白质环境在氧化过程中的作用的信息。
