脱氮作用是生物圈中氮循环的重要组成部分，它可以把多种氮氧化合物还原生成氮气。大量氮氧化合物的排放，引起严重的环境问题，危害人体健康。而脱氮酶所包含的四种金属酶能够有效地还原氮氧化合物生成氮气，可以使氮氧化合物的污染得到有效控制。因此，研究脱氮酶的催化反应机理，对基础研究和环境保护都有极大的科学意义。本项目拟基于已知脱氮酶的晶体结构，采用量子化学（QM）和QM/MM组合方法，研究脱氮过程所包含的每一种金属酶的反应机理、酶活性位的几何和电子结构特征、酶催化反应的势能面以及蛋白质环境对反应机理的影响，最终揭示脱氮酶还原硝酸根到亚硝酸根、一氧化氮、一氧化二氮以及氮气的完整反应机理。通过这些研究，对金属酶活性位的脱氮机理和蛋白质环境对酶催化反应的影响等方面都有较深入的了解，从而为脱氮酶模型配位化合物和新型高效脱氮催化剂的设计，提供重要的理论基础。

Denitrification is a key component of the biogeochemical nitrogen cycle involved in the four-steps and five-electrons reduction of nitrate (NO3?) to nitrite (NO2?), nitric oxide (NO), nitrous oxide (N2O) and molecular nitrogen (N2). The emission of massive nitrogen oxides leads to serious environmental problems and causes actual harm to human health. In order to make effective control of pollution, the reduction of nitrogen oxides to molecular nitrogen can be performed by means of efficient, special and highly professional metalloenzyms. Thus, the study on the catalytic denitrification mechanism of metalloenzyme, is of great significance to the fundamental research and environmental protection. On the basis of the newly identified structure of metalloenzymes, extensive quantum chemistry (QM) and hybrid QM/MM calculations have been carried out to investigate the geometry conformations, electronic structural characteristics and plausible enzymatic catalytic reaction mechanism for the reduction of nitrate to molecular nitrogen. According to the present research, it can get deep insights into the denitrification mechanism and provide the theoretical foundation for the rational design efficient denitrification catalysts.