Rege A A, Song C Y, Bos H J, Dresden M H
Verna and Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030.
Vet Parasitol. 1989 Nov;34(1-2):95-102. doi: 10.1016/0304-4017(89)90169-6.
Dictyocaulus viviparus adult worms feed on pulmonary tissues and cause significant pathology in the bovine host. In this report, acidic extracts of these organisms were examined for cysteine proteinase activity. A soluble thiol-dependent proteinase with native molecular weight of approximately 25 kDa was isolated and partially purified. This enzyme had maximal activity at acidic pH and showed inhibitor susceptibilities similar to the vertebrate acidic cysteine proteinases. When stored at 4 degrees C, it was stable at pH 5.0 for at least 10 days and at pH 7.0 for at least 24 h. The D. viviparus cysteine proteinase was capable of degrading type I collagen and hemoglobin. It is suggested that this enzyme may be involved in the nutrition of this parasite and/or have the potential to contribute to bronchial pathology in cattle.
胎生网尾线虫成虫以肺组织为食，并在牛宿主中引起严重病变。在本报告中，对这些生物体的酸性提取物进行了半胱氨酸蛋白酶活性检测。分离并部分纯化了一种天然分子量约为25 kDa的可溶性巯基依赖性蛋白酶。该酶在酸性pH下具有最大活性，且显示出与脊椎动物酸性半胱氨酸蛋白酶相似的抑制剂敏感性。当在4℃下储存时，它在pH 5.0下至少稳定10天，在pH 7.0下至少稳定24小时。胎生网尾线虫半胱氨酸蛋白酶能够降解I型胶原蛋白和血红蛋白。提示该酶可能参与该寄生虫的营养摄取和/或有可能导致牛的支气管病变。
