ACASP, A GENE ENCODING A CATHEPSIN D-LIKE ASPARTIC PROTEASE FROM THE HOOKWORM ANCYLOSTOMA-CANINUM

Intestinal infection with the zoonotic hookworm Ancylostoma caninum ca n provoke human eosinophilic enteritis. A cDNA was isolated from A. ca ninum, using an oligonucleotide primer designed to hybridize to the re gion encoding the consensus, catalytic site residues D(32)TGSSNLW of a spartic proteases, This novel cDNA encoded an aspartic protease zymoge n of 422 amino acids, exhibiting 47% identity to the lysosomal asparti c protease of Aedes aegypti, 46% identity to tile aspartic protease of Schistosoma japonicum and 48.5% to human cathepsin D. Its deduced str ucture differed from that of cathepsin D in the loop 2 ''flap,'' which holds the substrate at the active site, and by the presence of a COOH -terminal extension of similar to 30 residues. (C) 1996 Academic Press ,Inc.