酶法脱酸是油脂脱酸领域的主要发展方向，但一直存在脱酸效果差的瓶颈问题。前期研究发现，偏甘油酯脂肪酶可显著提升油脂脱酸效果，但对不同油脂的脱酸效率存在较大差异，推测偏甘油酯脂肪酶对脂肪酸选择性的不同是导致脱酸效率差异的根本原因。本项目拟以脱酸效果较好和效率较高的偏甘油酯脂肪酶SMG1-F278N为研究对象，以专一性常数（kcat/Km）为考察指标，探究其对不同链长、饱和度和双键位置脂肪酸的选择性规律；并通过静态结构分析和分子模拟，确定影响其脂肪酸选择性的关键氨基酸位点，建立其脂肪酸选择性分子识别模型；进而结合定点突变验证，阐明其脂肪酸选择性分子机制，为深入认知偏甘油酯脂肪酶底物选择的调控机制及设计满足工业酶法脱酸应用的酶制剂奠定理论基础。

Enzymatic deacidification is the main development direction in the field of oil deacidification. However, the enzymatic deacidification exists the bottleneck problem of poor deacidification effect. Our previous studies found that partial glyceride lipase could significantly improve the deacidification effect of oils and fats, while it showed remarkable difference in deacidification efficiency towards different oils and fats, thus it was speculated that the difference in fatty acid selectivity of partial glyceride lipase is the root cause of the difference in deacidification efficiency. This project intends to take the partial glyceride lipase SMG1-F278N with better deacidification effect and higher efficiency as the research object and use specificity constant (kcat/Km) as the index of evaluation to explore its selectivity towards fatty acids with different chain lengths, saturations and double bond positions, and the key residues affecting fatty acid selectivity would be determined through static structural analysis and molecular simulation. Thus, the model of molecular recognition of fatty acid selectivity of partial glyceride lipase would be established and the molecular mechanism of its fatty acid selectivity would be clarified by combining site-directed mutagenesis. This project would provide the research foundation for understanding the regulatory mechanism of substrate selectivity of partial glyceride lipase and designing enzyme preparations for industrial enzymatic deacidification.