Four types of amino acid ionic liquids (AAILs) with chiral structure were used to modify Candida antarctica lipase B (CALB). The results showed that the catalytic activity at different temperatures and pH, thermostability, and tolerance to organic solvents of all modified lipases were improved. The composition and configuration of modifiers have great influence on the catalytic performance of the modified lipases. AAILs composed of l-proline exhibited better modification effect than those containing d-proline. The use of [N-AC-l-Pro] [Cl] led to the highest modification degree (47.92 %) of the lipase, which exhibited the highest hydrolytic activity (430.67 U/g), as well as enhanced thermal stability and tolerance to organic solvents. The structure of CALB was characterized by circular dichroism (CD) and fluorescence spectroscopy. It was found that the introduction of a modifier changes the secondary structure of CALB to a certain extent, and the microenvironment around the fluorescent group changed slightly. The structural stability of CALB modified with [N-AC-l-Pro] [Cl] and the mechanism of reaction were studied by molecular dynamics simulations. The molecular dynamics simulations of the native and modified CALB were performed for 20 ns at 300 and 328 K. The simulation results showed that the root mean square deviation (RMSD) and total energy of modified CALB were less than those of native CALB, indicating a more stable structure for the modified CALB. The root mean square fluctuation (RMSF) calculations showed that the rigidity of the modified CALB and the flexibility of the active center region were both enhanced. The solvent accessibility area (SASA) calculations showed that both hydrophilicity and hydrophobicity of the modified enzyme-protein were improved. The increase in radial distribution function (RDF) of water molecules confirmed that the number of water molecules around the active sites was also increased. Thus, the modified CALB has enhanced structural stability and higher hydrolytic activity towards the triglyceride substrates.

具有四种手性结构的氨基酸离子液体（AAIL）用于修饰南极假丝酵母脂肪酶B（CALB）。结果表明，所有改性脂肪酶在不同温度和pH下的催化活性，热稳定性和对有机溶剂的耐受性均得到改善。改性剂的组成和构型对改性脂肪酶的催化性能有很大影响。由1-脯氨酸组成的AAILs表现出比含有d-脯氨酸的AAIL更好的修饰效果。[N-AC- l的使用-Pro] [Cl]导致脂肪酶的最高修饰度（47.92％），表现出最高的水解活性（430.67 U / g），以及增强的热稳定性和对有机溶剂的耐受性。CALB的结构通过圆二色性（CD）和荧光光谱表征。发现改性剂的引入在一定程度上改变了CALB的二级结构，并且荧光基团周围的微环境略有改变。[N-AC- 1]修饰的CALB的结构稳定性通过分子动力学模拟研究了-Pro] [Cl]的反应机理。在300和328 K下对天然和修饰的CALB进行了20 ns的分子动力学模拟。仿真结果表明，修饰的CALB的均方根偏差（RMSD）和总能量均小于天然的CALB。修改后的CALB的结构更稳定。均方根波动（RMSF）计算表明，改进的CALB的刚度和活动中心区域的柔韧性都得到了增强。溶剂可及面积（SASA）计算表明，修饰酶蛋白的亲水性和疏水性均得到改善。水分子径向分布函数（RDF）的增加证实了活性位点周围的水分子数量也增加了。因此，改性的CALB具有增强的结构稳定性和对甘油三酸酯底物的更高的水解活性。