pH 值对柚皮素与甲基乙二醛反应的影响：一项动力学研究。
Effect of pH on the reaction between naringenin and methylglyoxal: A kinetic study.
机构信息
Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, Copenhagen N, 2200 Denmark.
出版信息
Food Chem. 2019 Nov 15;298:125086. doi: 10.1016/j.foodchem.2019.125086. Epub 2019 Jun 27.
Methylglyoxal (MGO) is a highly reactive ɑ-dicarbonyl compound that may adversely impact food quality and human health by modifying proteins. The kinetics of the reaction of naringenin with MGO was studied at pH 6-8 and 37 °C by UV-Vis spectrophotometry and reaction products were characterized by liquid chromatography-mass spectrometry (LC-MS/MS). The apparent second order rate constant (k) increased at pH above the lowest pKa value of naringenin, indicating deprotonated naringenin as the main reactant. A Lederer-Manasse type reaction mechanism is suggested, with dehydration of the MGO-dihydrate as a rate determining step. The quantitative data obtained in the present study was used to simulate the competitive reaction between MGO and nucleophilic amino acid residues (Lys, Arg and Cys) and naringenin in milk. It is predicted that naringenin will be able to efficiently trap MGO during storage of milk, although the reversible trapping of MGO by Cys residues is initially kinetically favourable.
甲基乙二醛（MGO）是一种高度反应性的α-二羰基化合物，它可以通过修饰蛋白质而对食品质量和人类健康产生不利影响。通过紫外-可见分光光度法研究了柚皮素与 MGO 在 pH 6-8 和 37°C 下的反应动力学，并通过液相色谱-质谱联用（LC-MS/MS）对反应产物进行了表征。在低于柚皮素最低 pKa 值的 pH 以上，表观二级速率常数（k）增加，表明去质子化的柚皮素是主要反应物。建议采用 Lederer-Manasse 型反应机制，其中 MGO 二水合物的脱水是速率决定步骤。本研究中获得的定量数据用于模拟 MGO 与亲核氨基酸残基（Lys、Arg 和 Cys）和牛奶中柚皮素之间的竞争反应。预测在牛奶储存过程中，柚皮素将能够有效地捕获 MGO，尽管 Cys 残基对 MGO 的可逆捕获最初在动力学上是有利的。
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