白前弹性蛋白酶抑制剂的制备及其性质的研究

用白前干根茎为原料,经缓冲液提取,硫酸铵分级沉淀以DEAE-纤维素52层析纯化,对水透析和冷冻干燥得到抑制剂。经聚丙烯酰胶凝胶电泳证明是均一的,分子量约为35000D;经等电聚焦法测得等电点为5.28。抑制剂与弹性蛋白酶的结合以pH8.8为最适,用pH对Ki作图求得该抑制剂对弹性蛋白酶的作用基团的pK值为6.5,经双倒数作图证明抑制剂对弹性蛋白酶的抑制属竞争性抑制,该抑制剂为世界上首先发现。

Preparation and Purification of Cyxexchum Stauutoxii Elastase Inhibitor (CSEI) by Routine Methods and Study on Its Properties

The finding of CSE1 is the first in the world. A Method using phosphate buffer extraction, ammonium sulfate precipitation and organic solvent part precipitation DEAE-cellulose 52 column chro-matography is described. By this method, its relative inhibitor activity is 15 u/mg. The CSE1 appeared homogeneous as indicated by PAGE and its MW is about 35 000 Dalton by same method. Isoelectronic point is 5. 28 by using isoelectronic focus method. The effect of pH on dissociation constant was examined at pH 8. 8- The plots of pKi against pH gave a pKi value of 6. 5. When congo-red elastin wasused as substrate, the data for 1/V and 1/[S] are plotted on a graph, and it is a competitive inhibition between CSE1 and porcine pancreatic elastase.