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- Title
A cysteine proteinase in the penetration glands of the cercariae of Tylodelphys excavata (Trematoda, Diplostomidae).
- Authors
T. Moczon
- Abstract
Abstract??A cysteine proteinase was detected in the penetration glands of the cercariae ofTylodelphys excavataand examined by means of biochemical and histochemical methods. The enzyme hydrolyzed azocoll, azocasein, azoalbumin, andN-benzoyl-l-arginine-4-nitroanilide at optimal pH?6.8, 6.4, 6.8, and 6.4, respectively, but was incapable of degrading elastin-orcein at the pH range of 6.0?10.0. Under histochemical conditions, the proteinase cleavedN-benzyloxycarbonyl-l-alanine-2-naphthyl ester andN-benzyloxycarbonyl-l-arginine-2-naphthylamide. A number ofN-blocked synthetic substrates withl-methionine,l-leucine, glycine,dl- andl-phenylalanine at the P1position were not hydrolyzed. The metal cation complexane ethylenediamine tetraacetic acid (EDTA) and the reducing compound dithioerythritol stimulated the proteinase activity, whereas 0.1?mM zinc sulfate and the specific thiol-blocking reagentp-hydroxymercuribenzoate inhibited it. The proteinase activity was also sensitive to phenylmethylsulfonyl fluoride, leupeptin, tosyl-lysyl-chloromethylketone, and tosyl-phenylalanyl-chloromethylketone. An electrophoretic separation of extract proteins under non-denaturing conditions, at an operative pH of 3.5, in the presence of 5?mM EDTA and 5?mM 2-mercaptoethanol, revealed one main band of a relatively high gelatinolytic activity and two to three faint bands of low and very low activity, one of which was produced by a non-glandular intracellular cysteine proteinase related to cathepsin B. The other faint bands presumably were produced by partly autolysed molecules of the enzyme from the penetration glands.
- Subjects
CYSTEINE proteinases; TREMATODA; PLATYHELMINTHES; PROTEINASES
- Publication
Parasitology Research, 2007, Vol 100, Issue 2, p299
- ISSN
0932-0113
- Publication type
Article
- DOI
10.1007/s00436-006-0266-0