FASCIOLA-HEPATICA - A SECRETED CATHEPSIN L-LIKE PROTEINASE CLEAVES HOST IMMUNOGLOBULIN

Adult Fasciola hepatica secrete a cysteine proteinase capable of cleav ing host IgG close to the papain cleaving site. The proteinase was sep arated by size permeation chromatography. Gelatin-substrate polyacryla mide gel electrophoresis analysis revealed that the proteinase migrate s as 6 proteolytic bands in the apparent molecular size range 60-90 kD a. Based on pH profiles of activity, inhibition studies using diethylp yrocarbonate and the diazomethylketone Z-phe-ala-CHN2, and characteris ing the substrate specificity of the enzymes using fluorogenic peptide substrates we have shown that the 60-90-kDa proteinases are cathepsin L-like proteinases.