Day S R, Dalton J P, Clough K A, Leonardo L, Tiu W U, Brindley P J
Molecular Parasitology Unit, Queensland Institute of Medical Research, Royal Brisbane Hospital, Herston, Australia.
Biochem Biophys Res Commun. 1995 Dec 5;217(1):1-9. doi: 10.1006/bbrc.1995.2737.
Adult Schistosoma japonicum parasites synthesize and secrete both cathepsin L and cathepsin B cysteine proteinases. The specific activities of cathepsin L were many-fold higher than that of cathepsin B. The cDNAs encoding two distinct cathepsin L proteinases, here termed cathepsin L1 and L2, were isolated. The deduced amino acid sequences of the mature cathepsin L1 and L2 were approximately 41% identical, and moreover, S. japonicum cathepsin L2 showed more similarity with human cathepsin L than with schistosome cathepsin L1. Schistosome cathepsin L proteinases may be involved in the digestion of hemoglobin obtained from host erythrocytes. However, since we detected their presence in schistosome eggs, the release of these enzymes by eggs trapped in the liver and other organs may be associated with the granulomatous responses which characterize the pathology of human schistosomiasis.
日本血吸虫成虫能合成并分泌组织蛋白酶L和组织蛋白酶B这两种半胱氨酸蛋白酶。组织蛋白酶L的比活性比组织蛋白酶B高很多倍。我们分离出了编码两种不同组织蛋白酶L蛋白酶（这里称为组织蛋白酶L1和L2）的cDNA。成熟的组织蛋白酶L1和L2推导的氨基酸序列约41%相同，此外，日本血吸虫组织蛋白酶L2与人组织蛋白酶L的相似性高于与血吸虫组织蛋白酶L1的相似性。血吸虫组织蛋白酶L蛋白酶可能参与从宿主红细胞获取的血红蛋白的消化。然而，由于我们在血吸虫卵中检测到了它们的存在，被困在肝脏和其他器官中的虫卵释放这些酶可能与人类血吸虫病病理学特征性的肉芽肿反应有关。
