Helminthic cysteine proteases are well known to play critical roles in tissue invasion, nutrient uptake, and immune evasion of the parasites. In the same manner, the sparganum, the plerocercoid of Spirometra mansoni, is also known to secrete a large amount of cysteine proteases. However, cysteine protease inhibitors regulating the proteolytic activities of the cysteine protease are poorly illustrated. In this regard, we partially purified an endogenous cysteine protease inhibitor from spargana and characterized its biochemical properties. The cysteine protease inhibitor was purified by sequential chromatographies using Resource Q anion exchanger and Superdex 200 HR gel filtration from crude extracts of spargana. The molecular weight of the purified protein was estimated to be about 11 kD on SDS-PAGE. It was able to inhibit papain and 27 kDa cysteine protease of spargana with the ratio of 25.7% and 49.1%, respectively, while did not inhibit chymotrypsin. This finding suggests that the cysteine protease inhibitor of spargana may be involved in regulation of endogenous cysteine proteases of the parasite, rather than interact with cysteine proteases from their hosts.
Animals ; Cystatins/pharmacology ; Cysteine Endopeptidases/metabolism ; Cysteine Proteinase Inhibitors/chemistry/*metabolism/*pharmacology ; Helminth Proteins/*metabolism/*pharmacology ; Spirometra/*metabolism

A 29 kDa cysteine protease of Taenia solium metacestodes was purified by Mono Q anion-exchanger and Superose 6 HR gel filtration chromatography. The enzyme was effectively inhibited by cysteine protease inhibitors, such as iodoacetic acid (IAA) and trans-epoxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) while inhibitors acting on serine- or metallo-proteases did not affect the enzyme activity. The purified enzyme degraded human immunoglobulin G (IgG), collagen and bovine serum albumin (BSA), but human IgG was more susceptible for proteolysis by the enzyme. To define the precise biological roles of the enzyme, more detailed biochemical and functional studies would be required.
Taenia solium/*enzymology ; Serum Albumin, Bovine/metabolism ; Leucine/analogs & derivatives/pharmacology ; Iodoacetic Acid/pharmacology ; Immunoglobulin G/metabolism ; Humans ; Cysteine Proteinase Inhibitors/pharmacology ; Cysteine Endopeptidases/chemistry/*isolation & purification/metabolism ; Collagen/metabolism ; Chromatography, Ion Exchange ; Chromatography, Gel ; Animals

Because of the complexity of the cathepsin B-like (CBL) family, an information on the biological and biochemical characteristics of individual CBL genes is lacking. In this study, we investigated the degradative effects of the recombinant HC58 protein isolated from Haemonchus contortus parasites on protein substrates over a broad pH range in vitro. This protein, which hydrolyzed the synthetic peptide substrates Z-FR-AMC and Z-RR-AMC, had characteristics of the cysteine protease class of proteins. In the acidic pH range, the isolated protein actively degraded hemoglobin (Hb), the heavy chain of goat immunoglobulin G, and azocasein. By contrast, it degraded fibrinogen in the alkaline pH range. These activities were strongly inhibited in the presence of the cysteine protease inhibitor E-64. While the protein digested Hb, it did not induce the agglutination of erythrocytes from its natural host. These results suggest that the HC58 protein may play a role in the nutrition of this parasite.
Animals ; Caseins/metabolism ; Cathepsin B/antagonists&inhibitors/*genetics/isolation & purification/*metabolism ; Cysteine Proteinase Inhibitors/pharmacology ; DNA, Complementary/genetics ; Goat Diseases/*parasitology ; Goats ; Haemonchiasis/parasitology/*veterinary ; Haemonchus/*enzymology/genetics/isolation & purification ; Hemagglutination Tests/veterinary ; Hemoglobins/metabolism ; Hydrogen-Ion Concentration ; Immunoglobulin G/metabolism ; Leucine/analogs & derivatives/pharmacology ; RNA, Helminth/chemistry/genetics ; Recombinant Proteins/genetics/metabolism ; Reverse Transcriptase Polymerase Chain Reaction/veterinary