Siegbahn Per E M
Department of Physics, Stockholm Centre for Physics, Astronomy and Biotechnology, Stockholm University, S-106 91 Stockholm, Sweden.
Faraday Discuss. 2003;124:289-96; discussion 343-52, 453-5. doi: 10.1039/b211811b.
In applications on mechanisms for metalloenzymes, the hybrid density functional method B3LYP has been used in most cases. The present knowledge about the accuracy of this method on transition metal complexes is described. In comparison to ab initio methods like CASPT2 and CCSD(T), B3LYP has generally been shown to perform quite well. However, there is one exception and this is for the type of copper dimer which is found in enzymes like hemocyanin, catechol oxidase and tyrosinase. Large deviations have been found between CASPT2 and B3LYP and also between B3LYP and experiments on model complexes. This situation is carefully investigated. The accuracy of B3LYP for the activation of O2 in enzymes is also analyzed by comparisons to experiments. For the barrier of O-O bond cleavage B3LYP appears to behave quite satisfactorily, while for the binding of O2 to the metal there are deviations compared to experiment. The question whether this is due to the B3LYP method or to the chemical models used is addressed.
在金属酶作用机制的应用中，大多数情况下使用的是杂化密度泛函方法B3LYP。本文描述了目前关于该方法对过渡金属配合物准确性的认识。与诸如CASPT2和CCSD(T)等从头算方法相比，B3LYP通常表现得相当不错。然而，有一个例外，这就是在血蓝蛋白、儿茶酚氧化酶和酪氨酸酶等酶中发现的铜二聚体类型。在CASPT2和B3LYP之间以及B3LYP与模型配合物实验之间都发现了很大偏差。对这种情况进行了仔细研究。还通过与实验比较分析了B3LYP对酶中O2活化的准确性。对于O - O键断裂的势垒，B3LYP表现得相当令人满意，而对于O2与金属的结合，与实验相比存在偏差。探讨了这是由于B3LYP方法还是所使用的化学模型所致的问题。
