Kato Koichi, Nakayoshi Tomoki, Shinohara Yasuro, Kurimoto Eiji, Oda Akifumi, Ishikawa Yoshinobu
Faculty of Pharmaceutical Sciences, Shonan University of Medical Sciences, 16-48 Kamishinano, Totsuka-ku, Yokohama 244-0806, Japan.
Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan.
J Phys Chem B. 2024 May 23;128(20):4952-4958. doi: 10.1021/acs.jpcb.4c01231. Epub 2024 May 10.
The Maillard reaction is one of the nonenzymatic post-translational modifications of proteins. Products of this reaction are considered to be related to aging diseases and the sensation of taste. In the initial stage of the Maillard reaction, Schiff base formation first occurs by the nucleophilic attack of amine nitrogen in proteins, and then, the reaction proceeds through the formation of 1,2-eminal and Amadori compounds. In this study, we computationally investigated the reaction pathway of Schiff base formation from hexoses. The optimized geometries of energy minima and transition states were calculated by using the density functional theory with the CAM-B3LYP/6-311+G(2d,2p) level of theory. The Schiff base formation progressed through three steps: two steps of carbinolamine formation and one step of dehydration. The dehydration is considered to be the rate-determining step in all hexoses because the activation barrier of the dehydration was higher than that of the carbinolamine formation. Furthermore, the steric configuration of the OH group at positions 2 and 3 affected the activation barrier.
美拉德反应是蛋白质非酶促翻译后修饰之一。该反应的产物被认为与衰老疾病和味觉有关。在美拉德反应的初始阶段，首先通过蛋白质中胺氮的亲核攻击形成席夫碱，然后反应通过形成1,2 - 烯胺和阿马多里化合物继续进行。在本研究中，我们通过计算研究了由己糖形成席夫碱的反应途径。使用密度泛函理论在CAM - B3LYP/6 - 311 + G(2d,2p)理论水平下计算了能量最小值和过渡态的优化几何结构。席夫碱的形成分三步进行：两步形成氨基醇和一步脱水。脱水被认为是所有己糖中的速率决定步骤，因为脱水的活化能垒高于氨基醇形成的活化能垒。此外，2位和3位OH基团的空间构型影响活化能垒。
