Tamashiro W K, Rao M, Scott A L
J Parasitol. 1987 Feb;73(1):149-54.
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.
在犬恶丝虫微丝蚴的水提物中检测到了蛋白酶。提取物中的酶能够在pH值为7、8和9的条件下水解一种通用的蛋白酶底物偶氮酪蛋白。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酪蛋白水解酶，其中最主要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，在微丝蚴提取物中鉴定出了2种抗SDS、对巯基乙醇敏感的蛋白酶，分子量分别为22 kDa和76 kDa。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。经过20小时的孵育，微丝蚴提取物将放射性标记的IgG水解成8 - 10 kDa的片段。当使用活的微丝蚴时，在2小时内观察到了类似程度的消化。本文讨论了这些蛋白酶在逃避宿主效应机制方面的潜在意义。
