赤小豆胰蛋白酶抑制剂的分离纯化及其性质研究

用酸抽提、2.5％TCA热处理、硫酸铵盐析、凝胶层析和DEAE纤维素离子交换层析等方法,从中药赤小豆中分离得到一种胰蛋白酶抑制剂。聚丙烯酰胺凝胶电泳呈单一谱带。经SDS-聚丙烯酰胺凝胶电泳法测定,其分子量为7400。N-末端分析和氨基酸组成测定结果表明,赤小豆胰蛋白酶抑制剂不含半胱氨酸和胱氨酸,是以酪氨酸为N-末端,由54个氨基酸残基组成的单一多肽链。它仅对胰蛋白酶有较强的抑制作用,对胰凝乳蛋白酶、枯草杆菌蛋白酶和木瓜蛋白酶均无明显的抑制活力,对热及酸碱亦较稳定。

Studies on the Isolation and Charcterization of the Trypsin Inhibitor from Chi-xiao-dou(the seeds of Phaseolus Calcaratus Roxb)

A trypsin inhibitor were isolated and purifed from the chinese traditional medicine Chi-xiao-dou(the seeds of Phaseolus Calcaratus Roxb)by extraction with diluted H_2SO_4, 2.5% TCA heat handle, ( NH_4 )_2 SO_4, salting out, sephadex G-50 gel chromatography and ion exchang chromatography on DEAE-cellulose etc. It appeared as a single band on polyacrylamide get electrophoresis. The moleculaweight of the inhibitor were determined by means of electrophoresis on SDSr polyacrylamide gel about 7400. The analysis of the N-terminal amino acid and determine of the amino acid composition results proved that, it has no eystine and cysteine, fifty four of amino acid residues may go to make up the inhibitor from Chi-xiao-dou and it is a single polypeptide chain with N-terminal amino acid of tyrosine.It has stronger inhibition on trypsin, and has not inhibition on chymotrypsin subtilisin, papain. It is stability for heat and acid or base.