What Are the Differences between Ascorbic Acid and NADH as Hydride and Electron Sources in Vivo on Thermodynamics, Kinetics, and Mechanism?
作者:Xiao-Qing Zhu、Yuan-Yuan Mu、Xiu-Tao Li
DOI:10.1021/jp2067974
日期:2011.12.15
respectively, which indicates that iAscH– is a good electron donor and a good hydrogen atom donor, but GluNAH is a good hydride donor. The kinetic intrinsic barrier energy of iAscH– to release hydride anion in acetonitrile is larger than that of GluNAH to release hydride anion in acetonitrile by 6.9 kcal/mol. The mechanisms of hydride transfer from iAscH– and GluNAH to phenylxanthium perchlorate (PhXn+)
抗坏血酸(AscH 2)和二氢神经酰胺酰胺腺嘌呤二核苷酸(NADH)是两个非常重要的天然氧化还原辅助因子,可以用作氢化物,电子和氢原子来源,参与体内许多重要的生物还原过程。通过使用5,6-异亚丙基抗坏血酸酯(iAscH –)和β- d-吡喃葡萄糖基-1,4-二氢烟碱酰胺检查了两种天然还原剂氢化物,氢原子和电子供体在热力学,动力学和机理上的差异。分别以醋酸纤维(GluNAH)为模型。结果表明,iAscH –的氢化物供体能力比GluNAH小6.0 kcal / mol,但iAscH的电子供体能力和氢供体能力-分别比GluNAH的大20.8和8.4 kcal / mol,这表明iAscH –是良好的电子供体和良好的氢原子供体,而GluNAH是良好的氢化物供体。iAscH –在乙腈中释放氢化物阴离子的动能内在能垒比GluNAH在乙腈中释放氢化物阴离子的动能垒能大6.9 kcal / mol。从iA