牛蛙血浆半胱氨酸蛋白酶抑制剂（CPI）。

Bullfrog plasma cysteine proteinase inhibitor (CPI).

作者信息

Mashiko H, Takahashi H

机构信息

Division of Chemistry of Hygiene, Meiji College of Pharmacy, Tokyo, Japan.

出版信息

Immunopharmacology. 1996 May;32(1-3):91-3. doi: 10.1016/0162-3109(96)88183-5.

DOI:10.1016/0162-3109(96)88183-5

PMID:8796276

Abstract

Papain is inhibited by bullfrog plasma. CPI was isolated from bullfrog plasma by two step column chromatography; Cm-papain agarose column chromatography followed by FPLC Mono Q column chromatography with addition of benzamidine. Isolated CPI gave a single band on SDS-PAGE under reducing condition, and the molecular weight of reduced CPI was estimated to be over 200 kDa. When the isolated CPI was stored at 4 degrees C in the absence of benzamidine, the CPI was cleaved and yielded a protein consisting of heavy chain (60 kDa) and light chain (54 kDa). Both chains were linked with disulfide bond(s). The cleaved form of CPI was also isolated from the plasma in the absence of benzamidine. Intact and cleaved form of CPI inhibited papain and ficin, but not trypsin.

摘要

木瓜蛋白酶被牛蛙血浆抑制。通过两步柱色谱法从牛蛙血浆中分离出木瓜蛋白酶抑制剂（CPI）；先用Cm-木瓜蛋白酶琼脂糖柱色谱法，然后在添加苯甲脒的情况下进行快速蛋白质液相色谱法（FPLC）Mono Q柱色谱法。在还原条件下，分离得到的CPI在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）上呈现单一条带，还原型CPI的分子量估计超过200 kDa。当分离得到的CPI在没有苯甲脒的情况下于4℃储存时，CPI会被切割，产生一种由重链（60 kDa）和轻链（54 kDa）组成的蛋白质。两条链通过二硫键相连。在没有苯甲脒的情况下，也从血浆中分离出了切割形式的CPI。完整形式和切割形式的CPI均能抑制木瓜蛋白酶和无花果蛋白酶，但不能抑制胰蛋白酶。