Surface‐induced changes in the structure and activity of enzymes physically immobilized at solid/liquid interfaces
Surface‐induced changes in the structure and activity of enzymes physically immobilized at solid/liquid interfaces
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DOI：
10.1111/j.1470-8744.1998.tb00523.x
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发表时间：
1998-10
影响因子：
2.8
通讯作者：
W. Norde;T. Zoungrana
中科院分区：
文献类型：
--
作者：
W. Norde;T. Zoungrana
蛋白水解酶α -胰凝乳酶和脂溶酶角质酶从水溶液中吸附在不同疏水性和形态的固体表面上。这两种酶对疏水性较强的表面的吸附亲和力较大。水溶性，柔性低聚物接枝在吸附剂表面导致酶吸附减少。CD光谱和差示扫描量热法（DSC）表明，由于吸附，酶的结构发生了严重的扰动。CD光谱反映了整个蛋白质群体结构的平均值。DSC数据允许对吸附酶的构象状态的异质性得出额外的结论。结构扰动的程度，即结构被扰动的吸附分子的比例，在(1)疏水性较低，(2)含有水溶性柔性低聚物，(3)被蛋白质覆盖较多的表面较低。酶的比活性在吸附时或多或少地随结构扰动的程度而降低。与溶液中不同的是，在吸附状态下，热诱导失活过程与热诱导展开过程并不相同。此外，当酶被吸附时，它们的特定活性对温度变化的敏感性要低得多。
A proteolytic enzyme, α‐chymotrypsin, and a lipolytic enzyme, cutinase, were adsorbed from aqueous solutions on solid surfaces with different hydrophobicities and morphologies. With both enzymes the affinity of adsorption is larger for the more hydrophobic surface. Water‐soluble, flexible oligomers grafted on the sorbent surface cause a decrease in enzyme adsorption. CD spectroscopy and differential scanning calorimetry (DSC) indicate severe structural perturbations in the enzymes resulting from adsorption. The CD spectra reflect an average of the structure of the whole protein population. The DSC data allow additional conclusions to be drawn on the heterogeneity in the conformational states of the adsorbed enzymes. The degree of structural perturbation, that is the fraction of the adsorbed molecules of which the structure is perturbed, is lower at a surface that (1) is less hydrophobic, (2) contains water‐soluble flexible oligomers and (3) is more covered by the protein. The specific activities of the enzymes are decreased on adsorption, more or less following the extent of structural perturbation. Unlike in solution, in the adsorbed state the heat‐induced inactivation process is not identical with the heat‐induced unfolding process. Furthermore, when the enzymes are adsorbed their specific activities are much less sensitive to temperature variation.