Knauer D J, Orlando R A, Rosenblatt D
J Cell Physiol. 1987 Aug;132(2):318-24. doi: 10.1002/jcp.1041320217.
Protease nexin-I (PN-I, Mr approximately 43,000) is representative of a newly described class of cell-secreted protease inhibitors. PN-I has been purified to apparent homogeneity, partially sequenced, and monospecific antibodies have been raised against it. PN-I is a potent inhibitor of urokinase, thrombin, plasmin, and trypsin. In addition, cells have specific receptors that mediate the uptake of covalently linked complexes formed between PN-I and its protease substrates. In the present studies, we have investigated the relationship between human PN-I and a protease inhibitor derived from C6 glioma cells in culture that has neurite-promoting activity. On the basis of co-purification on heparin-Sepharose, identical molecular weight, antibody cross-reactivity, and receptor cross-reactivity, we conclude that PN-I and the glioma-cell-derived inhibitor are equivalent molecules.
蛋白酶连接素-I（PN-I，分子量约43,000）是新描述的一类细胞分泌的蛋白酶抑制剂的代表。PN-I已被纯化至表观均一，进行了部分测序，并制备了针对它的单特异性抗体。PN-I是尿激酶、凝血酶、纤溶酶和胰蛋白酶的有效抑制剂。此外，细胞具有特异性受体，可介导对PN-I与其蛋白酶底物之间形成的共价连接复合物的摄取。在本研究中，我们研究了人PN-I与培养的C6胶质瘤细胞衍生的具有神经突促进活性的蛋白酶抑制剂之间的关系。基于在肝素-琼脂糖上的共纯化、相同的分子量、抗体交叉反应性和受体交叉反应性，我们得出结论，PN-I和胶质瘤细胞衍生的抑制剂是等效分子。
