The effects of different concentrations of Hofmeister salts on the hydrolytic activity on triglycerides and the secondary structure of lipase B from Candida antarctica (CALB) were investigated. Structural changes after short- and long-time incubation at high salt concentrations were determined using circular dichroism (CD), fluorescence, and RMSD-RMSF simulations. At 5.2 M NaCl, the hydrolytic activity of CALB on tributyrin (TC4) and trioctanoin (TC8) was enhanced by 1.5 (from 817 ± 3.9 to 1228 ± 4.3 U/mg)- and 8.7 (from 25 ± 0.3 to 218 ± 2.3 U/mg)-folds compared with 0.15 M NaCl, respectively at pH 7.0 and 40 °C. An activity activation was seen with other salts tested; however, long-time incubation (24 h) did not result in retention of the activation effect for any of the salts tested. Secondary structure CD and fluorescence spectra showed that long-time incubation with NaCl, KCl, and CsCl provokes a compact structure without loss of native conformation, whereas chaotropic LiCl and CaCl₂ induced an increase in the α-helical content, and kosmotropic Na₂SO₄ provoked a molten globule state with rich β-sheet content. The RMSD-RMSF simulation agreed with the CD analysis, highlighting a principal salt-induced effect at the α-helix 5 region, promoting two different conformational states (open and closed) depending on the type and concentration of salt. Lastly, an increase in the interfacial tension occurred when high salt concentrations were added to the reaction media, affecting the catalytic properties. The results indicate that high-salt environments, such as 2–5.2 M NaCl, can be used to increase the lipolytic activity of CALB on TC4 and TC8.

研究了不同浓度的霍夫迈斯特盐对南极假丝酵母(CALB)甘油三酯水解活性和脂肪酶 B 二级结构的影响。使用圆二色性 (CD)、荧光和 RMSD-RMSF 模拟确定高盐浓度下短期和长期孵育后的结构变化。在 5.2 M NaCl 下，CALB 对三丁酸甘油酯 (TC4) 和三辛酸甘油酯 (TC8) 的水解活性增强了 1.5（从 817 ± 3.9 至 1228 ± 4.3 U/mg）和 8.7（从 25 ± 0.3 至 218 ± 2.3 U/mg） /mg) 倍，分别在 pH 7.0 和 40 °C 下与 0.15 M NaCl 相比。在测试的其他盐中观察到活性激活；然而，长时间孵育（24 小时）并没有导致任何测试的盐保留激活效果。二级结构 CD 和荧光光谱表明，与 NaCl、KCl 和 CsCl 长时间孵育会产生致密结构而不损失天然构象，而离液 LiCl 和 CaCl 2 会导致 α_螺旋含量增加，而离液 Na ₂ SO ₄引发了具有丰富β-折叠含量的熔球状态。RMSD-RMSF 模拟与 CD 分析一致，强调了 α-螺旋 5 区域的主要盐诱导效应，根据盐的类型和浓度促进两种不同的构象状态（开放和闭合）。最后，当向反应介质中添加高盐浓度时，界面张力会增加，从而影响催化性能。结果表明，高盐环境，例如2-5.2 M NaCl，可用于增加CALB对TC4和TC8的脂肪分解活性。