Mast cell tryptase from pig lungs triggers infection by pneumotropic Sendai and influenza A viruses - Purification and characterization
Mast cell tryptase from pig lungs triggers infection by pneumotropic Sendai and influenza A viruses - Purification and characterization
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DOI：
10.1046/j.1432-1327.2000.01346.x
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发表时间：
2000-06-01
期刊：
影响因子：
--
通讯作者：
Kido, H
中科院分区：
文献类型：
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作者：
Chen, Y;Shiota, M;Kido, H
从猪肺中纯化出一种新型胰蛋白酶型丝氨酸蛋白酶，该蛋白酶可处理嗜肺仙台病毒和人甲型流感病毒的包膜融合糖蛋白前体。在SDS/PAGE上，经凝胶渗透色谱测定，纯化酶的蛋白带约为32 kDa，表观分子质量为120 kDa。免疫组化抗体显示该酶位于猪肺肥大细胞中。该酶的n端44个氨基酸序列与其他物种的肥大细胞胰蛋白酶具有80%的同源性。在所测试的抑制剂中，氟磷酸二异丙基、止痛药、白细胞介素、苄脒和一些蛋白质抑制剂，如粘液蛋白酶抑制剂和抑酶蛋白，抑制了这种酶的活性。肝素稳定了酶，但高离子强度条件没有，不像人肥大细胞胰蛋白酶。纯化后的酶能有效地处理仙台病毒的融合糖蛋白前体，缓慢地处理人甲型流感病毒的血凝素，并以剂量依赖的方式触发仙台病毒的传染性，尽管来自肺部的人肥大细胞胰蛋白酶β和大鼠肥大细胞胰蛋白酶（大鼠MCP-7）根本不处理这些融合糖蛋白。这些结果提示，猪肺肥大细胞胰蛋白酶可能是嗜肺病毒感染的触发因素。
A novel trypsin-type serine proteinase, which processes the precursors of the envelope fusion glycoproteins of pneumotropic Sendai and human influenza A viruses, was purified to homogeneity from pig lungs. On SDS/PAGE, the purified enzyme gave a protein band corresponding to about 32 kDa, and has an apparent molecular mass of 120 kDa, as determined by gel permeation chromatography. Immunohistochemical staining with antibodies against this enzyme revealed that the enzyme is located in pig lung mast cells. The N-terminal 44-amino-acid sequence of the enzyme exhibits about 80% identity with those of mast cell tryptases from other species. Of the inhibitors tested, di-isopropyl fluorophosphate, antipain, leupeptin, benzamidine and a few proteinaceous inhibitors, such as mucus protease inhibitor and aprotinin, inhibited this enzyme activity. Heparin stabilized the enzyme, but high-ionic-strength conditions did not, unlike for human mast cell tryptase. The purified enzyme efficiently processed the fusion glycoprotein precursor of Sendai virus and slowly processed hemagglutinin of human influenza A virus, and triggered the infectivity of Sendai virus in a dose-dependent manner, although human mast cell tryptase beta and rat mast cell tryptase (rat MCP-7) from lungs did not process these fusion glycoproteins at all. These results suggest that mast cell tryptase in pig lungs is the possible trigger of the pneumotropic virus infections.