菠萝蛋白酶部分酶学性质的研究

通过菠萝蛋白酶的最佳吸收峰、酶的浓度及大小，红外光谱分析和酶活性的测定，研究菠萝蛋白酶的部分性质。结果表明，菠萝蛋白酶具有热稳定性，其大小约为28.8 kD ，且最适温度为60℃，最适p H为7.5。Fe^2＋对菠萝蛋白酶有激活作用，Z n^2＋、C u^2＋低浓度有促进作用，高浓度有抑制作用，NaCl对菠萝蛋白酶能起到一定的保护作用、KCl对酶反应影响不大，MgSO4·7H2O和无水CaCl2对菠萝蛋白酶活性均有一定程度的抑制作用。菠萝蛋白酶经pH2.5胃蛋白酶和 pH3.2胃蛋白酶作用后，随处理时间的延长，其酶活力都呈下降的趋势。其中，pH2.5条件下的胃蛋白酶对菠萝蛋白酶活力的影响较大。表明在模拟猪胃条件下pH2.5胃蛋白酶对菠萝蛋白酶影响较大。

Study of Enzymatic Properties of Bromelain

Study some properties of bromelain by measuring best absorption peak , concentration and size of bromelain ,infrared spectroscopic analysis and determination of enzyme activity . The results showed that bromelain has thermal stability ,and its size is about 28.8 kD ,and the optimum temperature is 60℃ ,the optimum pH is 7.5.Additional Fe^2＋ can increase the activity ,low concentration of Zn^2 ＋ ,Cu^2 ＋ can promote the activity and high concentration of them can inhibit the activity .The result also showed that NaCl has a protective effect and KCl had little effect on the enzyme activity ,while MgSO4 · 7H2 O and CaCl2 could inhibit the activity .The bromelain activity tended to decrease with the extension of treatment time of pepsin on pH 2.5 and 3.2. Among them ,pepsin on pH2.5 has greater impact on the activity of bromelain . In simulated pig gastric conditions ,pepsin on pH2.5 has greater effect on the activity of bromelain .