Department of Chemistry and Chemical Biology, The University of New Mexico, MSC02 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001, USA.
Chem Biodivers. 2012 Sep;9(9):1756-60. doi: 10.1002/cbdv.201200073.
We have performed a computational study of substrate C-H bond activation in enzymes of the XO family. The C-H H-atom for all XO substrates studied is transferred to the terminal sulfido at the transition state with near neutral charge, and this is consistent with both Mo=S π→ C-H σ* and C-H σ→Mo=S π* donor-acceptor interactions activating the C-H bond. A C-H bond scission and Mo reduction appear to be highly correlated along the reaction coordinate for all XO substrates studied, with Mo reduction being a continuous and exponential function of C-H bond breaking along the reaction coordinate.
我们对 XO 家族酶中的底物 C-H 键活化进行了计算研究。所有研究的 XO 底物的 C-H H-原子在过渡态转移到末端的硫代物，带近中性电荷，这与 Mo=S π→ C-H σ和 C-H σ→Mo=S π供体-受体相互作用均一致，能激活 C-H 键。对于所有研究的 XO 底物，C-H 键的断裂和 Mo 的还原似乎在反应坐标上高度相关，Mo 的还原是 C-H 键沿着反应坐标断裂的连续和指数函数。
