Proteolytic cleavage of IgG and other protein substrates by Dirofilaria immitis microfilarial enzymes.
Proteolytic cleavage of IgG and other protein substrates by Dirofilaria immitis microfilarial enzymes.
复制标题
恶丝虫微丝蚴酶对 IgG 和其他蛋白质底物进行蛋白水解裂解。
作者：
W. K. Tamashiro;M. Rao;A. Scott
微丝芽孢丝虫水提液中检测到蛋白酶。提取物中的酶能够在pH为7,8和9时水解一般蛋白酶底物Azocoll。对多种蛋白酶抑制剂的敏感性表明，提取物中存在多种偶氮溶酶，其中最突出的似乎属于丝氨酸类蛋白酶。通过将各种底物掺入聚丙烯酰胺凝胶基质中，在22和76 kDa处鉴定出MF提取物中的2种抗sds、巯基乙醇敏感的蛋白酶。这些蛋白酶在消化酪蛋白、纤维蛋白原、血红蛋白和IgG方面表现出不同的能力。在20小时的孵育后，MF提取物将放射性标记的IgG水解成8-10 kda的片段。当使用有活力的微丝虫时，在2小时内观察到类似程度的消化。讨论了这些蛋白酶在逃避宿主效应机制中的潜在意义。
Proteases were detected in aqueous extracts of Dirofilaria immitis microfilariae. Enzymes within the extract were capable of hydrolyzing Azocoll, a general protease substrate, at pH's 7, 8, and 9. Sensitivities to a variety of protease inhibitors indicated that multiple azocollytic enzymes were present in the extract, most prominent of which appear to belong to the serine class of proteases. By incorporating various substrates into the matrices of polyacrylamide gels, 2 SDS-resistant, mercaptoethanol-sensitive proteases in the MF extract were identified at 22 and 76 kDa. These proteases showed differential abilities to digest casein, fibrinogen, hemoglobin, and IgG. The MF extract hydrolyzed radiolabeled IgG into 8-10-kDa fragments following a 20-hr incubation. A similar degree of digestion was observed in 2 hr when viable microfilariae were used. The potential significance of these proteases in the evasion of host effector mechanisms is discussed.