HYDROLYSIS OF HEMOGLOBIN BY SCHISTSOMA MANSONI CATHEPSIN B-LIKE CYSTEINEPROTEASE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In the initial analysis for this project, purified recombinant Schistosome cathepsin B was incubated with hemoglobin, and fragments of hemoglobin degradation identified. Initial cleavage appeared to be in a "weak link" of the hemoglobin chain known to be cleaved by other hemoglobin degrading proteases. Subsequent degradation was rapid and yielded only small peptide fragments. This study confirmed the efficacy of the schistosome cathepsin B as a "hemoglobinase". Current efforts are aimed at validating hemoglobin and other host-serum proteins as substrates for schistosome digestive proteases in a more "in vivo" setting. Contents of schistosome guts regurgitated following development in mouse models of infection are being separated and analyzed for specific protein fragments. We are planning to identify both what substrates are cleaved, as well as the sites of cleavage so that we can use this information to identify putative proteases from the schistosome gut that may be responsible for specific cleavage fragments.