title: Aspartic protease activities of schistosomes cleave mammalian hemoglobins in a host-specific manner.
abstract: We examined the efficiency of digestion of hemoglobin from four mammalian species, human, cow, sheep, and horse by acidic extracts of mixed sex adults of Schistosoma japonicum and S. mansoni. Activity ascribable to aspartic protease(s) from S. japonicum and S. mansoni cleaved human hemoglobin. In addition, aspartic protease activities from S. japonicum cleaved hemoglobin from bovine, sheep, and horse blood more efficiently than did the activity from extracts of S. mansoni. These findings support the hypothesis that substrate specificity of hemoglobin-degrading proteases employed by blood feeding helminth parasites influences parasite host species range; differences in amino acid sequences in key sites of the parasite proteases interact less or more efficiently with the hemoglobins of permissive or non-permissive hosts.
authors.affiliation: Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Koehler
authors.forename: Maria E
authors.initials: ME
authors.lastname: Morales
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Shelby
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Brindley
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D002417:Cattle; D006454:Hemoglobins / Q000378:metabolism*; D006736:Horses; D006790:Host-Parasite Interactions; D006801:Humans; D006868:Hydrolysis; D051379:Mice; D012549:Schistosoma japonicum / Q000201:enzymology*; D012550:Schistosoma mansoni / Q000201:enzymology*; D012756:Sheep; D013379:Substrate Specificity
chemical_list: D006454:Hemoglobins; D016282:Aspartic Acid Endopeptidases