酶法催化脂质改性是制备高纯度的甘油三酯型DHA/EPA产品的有效途径，但现有的绝大多数脂肪酶难以实现高效快速地催化合成高纯度产品。我们的前期研究发现，来源于海洋放线菌的新型脂肪酶MAS1可以高效催化合成高纯度的甘油三酯型DHA/EPA，由此推测脂肪酶MAS1的催化机制可能不同于其他脂肪酶。本课题拟重点研究脂肪酶MAS1在甘油三酯型DHA/EPA合成过程中的催化特性，再结合脂肪酶MAS1的结构，采用分子对接等生物计算手段分析催化特性与酶分子活性氨基酸变化的相关性；对其活性氨基酸位点进行突变，并研究突变体在甘油三酯合成反应中的催化特性，揭示脂肪酶MAS1分子高效催化的反应机制。期望通过此研究，可推动酶工程领域的基础学科研究和甘油三酯型DHA/EPA生产工艺研究的源头创新，同时为脂肪酶MAS1的工程化应用提供坚实的理论基础。

Enzymatic modification of lipids offers an effective way to produce high-purity DHA/EPA-rich triacylglycerols (TAG). However, DHA/EPA-rich TAG are difficult to be synthesized efficiently by most of lipases. Our previous studies have found that highly efficient synthesis of high-purity DHA/EPA-rich TAG can be achieved by new lipase MAS1 from marine Streptomyces sp. strain W007. Thus, it is conferred that the catalytic mechanism of lipase MAS1 may be different from those of other lipases. In this project, lipase MAS1 will be employed to synthesize DHA/EPA-rich triacylglycerols and its characteristics in the reaction process will be investigated. Computational biology approaches, such as molecular docking, will be utilized to analyze the relationship between the possible key amino acid moieties and the catalytic characteristics. The mutants of lipase MAS1 will be produced by site-directed mutagenesis and their catalytic characteristics will be investigated in the production of triacylglycerols. The catalytic mechanism of lipase MAS1 will be revealed by analyzing catalytic parameters and three-dimensional structure. The research is of significant for the basic research of enzyme engineering, and will push the innovative proceeding of the synthesis of DHA/EPA-rich triacylglycerols. The research also provides a theoretical basis for the engineering application of lipase MAS1.