眼镜蛇毒中一个弱纤维蛋白原水解活性金属蛋白酶的纯化和性质研究

通过蛋白层析从中华眼镜蛇毒中分离纯化出一个新的纤维蛋白原水解酶atrase A. Atrase A是一个分子量为64.6 kD,等电点为pH 9.6和中性糖含量为4.16%的碱性单链糖蛋白.它具有弱的纤维蛋白原α链水解活性.该活性能被金属螯合剂EDTA, EGTA,1,10 phenanthroline和还原剂DTT完全抑制，而PMSF只能部分抑制该活性，大豆胰蛋白酶抑制剂对其没有影响， 表明atrase A属于金属蛋白酶. Atrase A具有水肿活性和金黄色葡萄球菌抑制活性.它对A549 和K562 细胞没有细胞毒性，但能使贴壁生长的A549细胞解离悬浮. Atrase A没有纤维蛋白、azocasein 、BAEE水解活性，对ADP、胶原诱导的血小板聚集没有明确的抑制作用. 经小鼠皮下注射后没有发现其有出血毒活性.

Purification and Characterization of a Metalloproteinase with Weak Fibrinogenolytic Activity from Naja atra Venom

A novel fibrinogenolytic protease,named atrase A,has been purified from the venom of Naja atra by sequential chromatography.Atrase A is a single chain glycoprotein with a molecular weight of 64.6 kD,an isoelectric point of pH 9.6 and a neutral sugar content of 4.16%.Atrase A specifically and slowly degraded α-chain of fibrinogen.This fibrinogenolytic activity Was inhibited by chelating agents(EDTA,EGTA and 1,10-phenanthroline)and DTY,and partially inhibited by PMSF,but not by soybean trypsin inhibitor,indicating it is a metalloproteinase.Atrase A showed edema-inducing activity and bactericidal activity against Staphylococcusa aureus.Atrase A did not show cytotoxicity on A549 and K562 cells in MTT assay,but detached adherent A549 cells from the substrate.Atrase A did not show significant inhibition of platelet aggregation induced by ADP or collagen,and did not exhibit proteolytic activities towards fibrin,azocasein and BAEE.It also did not show hemorrhage activity when injected subcutaneously into mice.