Dubovi E J, Geratz J D, Tidwell R R
Infect Immun. 1983 Apr;40(1):351-8. doi: 10.1128/iai.40.1.351-358.1983.
A series of proteases of diverse substrate specificity were tested for their effect on respiratory syncytial virus-induced cytopathology. Three of the enzymes, thrombin, plasmin, and trypsin, were able to augment significantly the fusion of virus-infected A549 cells. On a concentration basis, thrombin was the most active promoter, followed by plasmin and then trypsin. Hirudin, a specific thrombin inhibitor, blocked the fusion-enhancing property of thrombin, yet had no influence on the basal rate of fusion in the absence of the enzyme. By contrast, the amidine-type inhibitors of trypsin-like proteases, bis(5-amidino-2-benzimidazolyl)-methane (BABIM), blocked not only the thrombin effect, but also the fusion in the thrombin-free controls. The suppressive activity of BABIM was observed at concentrations so low as to exclude any direct inhibitory effect on thrombin itself. These results make it seem very likely that thrombin advances cell fusion by activating a BABIM-sensitive protease. Plasmin and trypsin can be expected to act in a similar manner.
测试了一系列具有不同底物特异性的蛋白酶对呼吸道合胞病毒诱导的细胞病变的影响。其中三种酶，即凝血酶、纤溶酶和胰蛋白酶，能够显著增强病毒感染的A549细胞的融合。以浓度为基础，凝血酶是最活跃的促进剂，其次是纤溶酶，然后是胰蛋白酶。水蛭素，一种特异性凝血酶抑制剂，可阻断凝血酶的融合增强特性，但在无该酶的情况下对基础融合速率没有影响。相比之下，胰蛋白酶样蛋白酶的脒基型抑制剂双（5-脒基-2-苯并咪唑基）甲烷（BABIM）不仅阻断了凝血酶的作用，还阻断了无凝血酶对照组中的融合。在低至排除对凝血酶本身有任何直接抑制作用的浓度下就观察到了BABIM的抑制活性。这些结果使得凝血酶很可能通过激活一种对BABIM敏感的蛋白酶来促进细胞融合。可以预期纤溶酶和胰蛋白酶也以类似的方式起作用。
