多氯联苯(PCBs)是一类典型的持久性有机污染物(POPs)，已被首批列入《斯德哥尔摩公约》POPs的黑名单中。PCBs具有致癌、致畸、致突变效应及环境内分泌干扰效应。多氯联苯在工业上的广泛应用，已造成全球性环境污染，PCBs也是我国优先控制污染物之一。多氯联苯可在各种环境介质中降解，转化成安全无毒或毒性较低的产物，但也可能生成毒性更强、更稳定的二次污染物如二噁英。本项目拟采用量子化学计算与分子模拟(QM/MM)组合方法研究多氯联苯在生物酶作用下的降解，从分子水平上探讨其结构信息、降解机理、中间产物等；研究酶活性中心部位氨基酸对速控步骤的影响，尤其查明对速控步骤有抑制作用的氨基酸，有针对性的进行突变，构建更为高效的降解酶；将PCBs结构与其宏观的环境行为进行关联，建立多氯联苯降解性能预测模型。期望通过本项目的研究为有效控制多氯联苯污染乃至为我国履行POPs国际公约提供理论依据和科技支撑。

Phlorinated biphenyls (PCBs) are considered as typical persistent organic pollutants (POPs) and listed by the international Stockholm Convention as POPs. PCBs have carcinogenic,teratogenic,mutagenic and endocrine disrupting effects. Due to their widespread use, serious environmental problems are emerging, and they are among the priority pollutants in China. PCBs could degrade under various environmental conditions and transform to nontoxic or less toxic compounds. But some of them may also transform to more toxic second polltants such as dioxins. This project will study the degradation of PCBs with the aid of enzyme by using the quantum calculation and molecular simulation. The geometrical parameters, degradation mechanism and intermediates will be obtained from the molecular level. This project will also study the influence of the active center of enzyme, amino acid, on the rate determining step of the degradation processes. Especially, the amino acids, which depress the rate determining step, will be identified. And, this project will find more effective enzymes by means of mutation. This project will associate the structures of PCBs with their enviromental actions and construct the degradation model of PCBs. We hope that this project will help to develop more effective control strategies of PCBs and be of practical value for the international Stockholm Convention.