a1 Department of Biology, Imperial College of Science, Technology and Medicine, Prince Consort Road, South Kensington, London SW7 2BB
Excretory/secretory (E/S) material of Trichuris muris was found to contain 2 major peptidases, Mr 85 and 105 kDa, which degrade gelatin optimally at pH 6·0 in sodium dodecyl sulphate–polyacrylamide gels. The peptidases were inactivated diisopropylfluorophosphate, leupeptin and soybean trypsin inhibitor, but were unaffected by inhibitors of aspartic-, cysteine- and metallo-peptidases, indicating that they are serine peptidases. Both enzymes were detectable within 5 h after incubation of worms in culture medium and showed a time-dependent increase in levels. Neither peptidase was detected in worm extracts, suggesting that they are activated during or following secretion from worms. Live worms degraded radio-isotope labelled extracellular matrix protein substratum derived from mammalian cells. Aminopeptidase activities capable of catalysing hydrolysis of amino acyl aminomethylcoumarin (MCA) substrates and a Z-Phe-Arg-MCA-hydrolysing cysteine peptidase activity, were detected in extracts of adult worms but not in E/S material.
(Received February 12 1994)
(Revised April 16 1994)
(Accepted May 07 1994)
p1 Goodrich Laboratories, Zoology Department, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
p2 Liverpool School of Tropical Medicine and Hygiene, Pembroke Place, Liverpool L3 5QA, UK.
p3 Department of Psychiatry, Washington University School of Medicine, 4940 Children's Place, St Louis, Missouri 63110, USA.