甘薯和花生胰蛋白酶抑制剂的初步研究

Preliminary study on the trypsin inhibitors in the sweet potato and peanut

关键词:  胰蛋白酶抑制剂  等电聚焦电泳  底物

Key words:  trypsin inhibitor  isoelectric focusing electrophoresis  substrate

摘要:

许多植物蛋白制成品均含有抑制动物消化的蛋白酶抑制剂。目前已从某些豆类及蔬菜种子中分离出多种对胰蛋白酶具有抑制作用的活性物质。该实验以花生、甘薯等为原料,通过DEAE-Sepharose 4B FF阴离子交换柱层析分离胰蛋白酶抑制剂,以N-苯甲酰-L-精氨酸乙酯(BAEE)为底物测定其对胰蛋白酶的抑制活性; 将具有抑制活性的组分通过SDS-PAGE测定蛋白质相对分子质量(Mr); 以聚丙烯酰胺凝胶等电聚焦电泳测定蛋白质等电点(pI)。结果显示,甘薯中至少有4种胰蛋白酶抑制剂组分,相对分子质量为20～25 kD、等电点在pH5.0～6.6之间; 花生中至少有三种胰蛋白酶抑制剂组分,相对分子质量为30～70 kD、等电点在pH5.0～5.8之间。

Abstract:

The protease inhibitor inhibiting animal digestion exists in many plant products. Now,trypsin inhibitors have been isolated and purified from the beans and vegetable seeds. In this work,trypsin inhibitors were extracted and purified from peanut and sweet potato by DEAE-Sepharose 4B FF column. Then the inhibition activities of the trypsin inhibitors were determined using the BAEE as substrates. The relative molecular weight(Mr)and isoelectric point(pI)of trypsin inhibitors were determined by the SDS-PAGE and isoelectric focusing electrophoresis respectively. The results showed that there were at least four components of the trypsin inhibitors in the sweet potatoes. Mr was about 20-25 kD,pI was between 5.0-6.6 and there were at least three components of trypsin inhibitors in the peanuts,Mr was about 30-70kD,pI was between 5.0-5.8.