Lau H K, Lui A Y, Wong N S
Comp Biochem Physiol B. 1986;84(4):507-11. doi: 10.1016/0305-0491(86)90114-8.
A proteolytic enzyme could be isolated from rabbit serum by means of DEAE cellulose, Protein A-bound Sepharose and lysine-bound Sepharose chromatographies. This enzyme was found to be the major protease contaminating IgG preparations of rabbit serum. This enzyme was identified as plasmin because it displayed an apparent Mr of 90,000 on nonreduced SDS polyacrylamide gel electrophoresis, was able to directly lyse fibrin and the chromogenic substrate H-D-Val-Leu-Lys-p-nitroanilide, and was stable after heating at 56 degrees for 30 min but broke down at 80 degrees. Its Km toward the chromogenic substrate was 0.35 mM, which agreed well with the published value for plasmin.
通过DEAE纤维素、蛋白A结合的琼脂糖凝胶和赖氨酸结合的琼脂糖凝胶色谱法，可以从兔血清中分离出一种蛋白水解酶。发现这种酶是污染兔血清IgG制剂的主要蛋白酶。该酶被鉴定为纤溶酶，因为它在非还原SDS聚丙烯酰胺凝胶电泳上显示出明显的90,000的分子量，能够直接溶解纤维蛋白和发色底物H-D-缬氨酸-亮氨酸-赖氨酸-对硝基苯胺，并且在56℃加热30分钟后稳定，但在80℃分解。它对发色底物的Km为0.35 mM，与已发表的纤溶酶值非常吻合。
