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为了寻找具有药物作用的天然胰蛋白酶抑制物,采用硫酸铵分级沉淀、离子交换层析(DEAE-纤维素52)及Sephadex G-100凝胶层析等方法,从鹰嘴豆种子中分离出一种鹰嘴豆胰蛋白酶抑制剂(CPTI).研究表明:CPTI对胰蛋白酶有较强的抑制作用,抑制率达80%,而对胰凝乳蛋白酶抑制作用较弱,抑制率为32%,对胃蛋白酶、木瓜蛋白酶及枯草杆菌蛋白酶均无抑制作用;用SDS-PAGE测得CPTI近似分子质量为25.7 kD;CPTI具有较高的热稳定性,在100℃下加热60min,对胰蛋白酶活性仍保持78%抑制率;Lineveaer-Burk作图得知该抑制剂属竞争性抑制类型.动力学测定显示,来自鹰嘴豆中的CPTI对胰蛋白酶的抑制作用常数(Ki)为3.99×10-7 mol/L.
In order to find a natural trypsin inhibitor with drug action, ammonium sulfate fractionation, ion exchange chromatography (DEAE-cellulose 52), and Sephadex G-100 gel chromatography were used to isolate one Chickpea trypsin inhibitor (CPTI) .Studies show that: CPTI has a strong inhibitory effect on trypsin, the inhibition rate of 80%, while the weak inhibition of chymotrypsin, the inhibition rate was 32%, for Pepsin, papain and subtilisin. The approximate molecular mass of CPTI measured by SDS-PAGE was 25.7 kD. CPTI had higher thermal stability and maintained the activity of trypsin at 100 ℃ for 60min 78% inhibition; Lineveaer-Burk plot that the inhibitor is a competitive inhibition type.Kinetic determination showed that the inhibitory effect constant (Ki) of CPTI from chickpea on trypsin was 3.99 × 10-7 mol / L.