Schistosoma mansoni: effect of some cations on the proteolytic enzymes of cercariae |
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Authors: | M H Dresden E M Edlin |
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Institution: | Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77025, U.S.A. |
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Abstract: | The effects of various salts on the proteolytic activity of extracts from Schistosoma mansoni cercariae were tested. Using an Azocoll substrate, stimulation (2 to 2.5-fold) of activity by the monovalent cations Na+ and K+ was demonstrated, with maximum stimulation at 20–40 mM concentrations. The divalent cations Mg2+ and Ca2+ stimulated proteolytic activity at low concentrations (between 0 and 10 mM) but inhibited activity at higher concentrations. The divalent cations Zn2+, Cu2+, Fe2+, and Co2+ were inhibitory even at very low concentrations. The results presented here are discussed in relation to previously described ion effects on cercarial infectivity. |
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Keywords: | Trematoda Cercariae Preacetabular glands Proteolytic enzymes Sephadex gel filtration Calcium Cations |
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