Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 27599, United States.
Bioorg Chem. 2010 Oct;38(5):224-8. doi: 10.1016/j.bioorg.2010.05.003. Epub 2010 Jun 4.
Previous estimates of the rate of spontaneous cleavage of the glycosidic bond of adenosine were determined by extrapolating the rates of the acid- and base-catalyzed reactions to neutral pH. Here we show that cleavage also proceeds through a pH-independent mechanism. Rate constants were determined as a function of temperature at pH 7 and a linear Arrhenius plot was constructed. Uncatalyzed cleavage occurs with a rate constant of 3.7x10(-12)s(-1) at 25 degrees C, and the rate enhancement generated by the corresponding glycoside hydrolase is approximately 5x10(12)-fold.
先前对腺苷糖苷键自发裂解速率的估计是通过将酸催化和碱催化反应的速率外推至中性 pH 值来确定的。在这里，我们表明裂解也可以通过一种与 pH 无关的机制进行。在 pH 7 时，速率常数随温度的变化而确定，并构建了一条线性阿伦尼乌斯图。在 25°C 时，无催化剂催化的裂解以 3.7x10(-12)s(-1)的速率常数发生，而相应糖苷水解酶产生的速率增强约为 5x10(12)倍。
