Abstract: The activity and stability of α-chymotrypsin in different media were studied. The influence of organic solvents, pH values, ionic strengths and ionic types on the stability of α-chymotrypsin was preliminarily studied. The secondary structure of α-chymotrypsin in different pH was studied by circular dichroism (CD) spectra. The results showed that α-chymotrypsin could maintain its high activity and stability in some organic solvents for a long time. And the CD spectra of α-chymotrypsin in solutions with different pH showed that in pH 10.0, the content of α-helix and (or) β-sheet of α-chymotrypsin was higher than that in pH 5.0 or pH 7.0. The influence of ionic strengths on the activity and stability of α-chymotrypsin was different in different pH values.

Key words: α-chymotrypsin, stability, pH value, ionic strength, CD spectra

摘要： 测定了α-胰凝乳蛋白酶在不同介质中的活性及稳定性。研究了有机溶剂性质、pH值、离子强度及离子类型对α-胰凝乳蛋白酶活性与稳定性的影响，并通过CD谱初步研究了α-胰凝乳蛋白酶在不同pH值缓冲液中的二级结构变化。研究结果表明，α-胰凝乳蛋白酶在某些有机溶剂中能在较长时间内维持较高的酶活性。α-胰凝乳蛋白酶在3种pH值不同的缓冲液中的CD谱表明其在pH＝10.0的稀溶液中的α-螺旋和（或）β-折叠含量较高。在不同pH值条件下，离子强度对α-胰凝乳蛋白酶的活性与稳定性的影响不同。

关键词: α-胰凝乳蛋白酶, 稳定性, pH值, 离子强度, CD谱