Asparaginyl endopeptidase activity in adult Schistosoma mansoni.
Sequence comparisons have recently shown that the Schistosoma mansoni protein Sm32 is similar to asparaginyl endoproteinases, a novel family of cysteine proteinases, of which the legumains from legumes are the best characterized. By synthesizing and employing fluorogenic peptide substrates for the specific detection of asparaginyl endopeptidases, we have identified this type of activity in extracts of adult S. mansoni. The S. mansoni activity is similar to that of the legumains in its substrate specificity and sensitivity to thiol inhibitors, but differs in its pH and temperature optima for activity. In contrast, unlike the legumains, the schistosome asparaginyl endopeptidase activity is not activated by the reducing agent dithiothreitol. As suggested for legumains, Sm32 may function in the post-translational modification processes that regulate the activity of other molecules.
Dalton
J P
JP
Molecular Parasitology Unit, Queensland Institute of Medical Research, Bancroft Centre, Royal Brisbane Hospital, Australia.
Hola-Jamriska
L
L
Brindley
P J
PJ
D000595:Amino Acid Sequence; D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010940:Plant Proteins; D011499:Protein Processing, Post-Translational; D012550:Schistosoma mansoni / Q000201:enzymology*; D000099240:Asparaginyl Endopeptidase
D003546:Cysteine Endopeptidases; D010940:Plant Proteins; D000099240:Asparaginyl Endopeptidase