title: Inhibitory effects of human alpha 2-macroglobulin on Trypanosoma cruzi epimastigote proteinases.
abstract: The inactivation of Trypanosoma cruzi proteinases by human alpha 2-macroglobulin (alpha 2-M), a major plasma proteinase inhibitor was studied. Evidences regarding the interaction between alpha 2-M and proteolytic enzymes contained in crude cell-free extracts of T. cruzi were derived from electrophoretic and enzymatic assays. The former showed conformational and structural changes occurring in alpha 2-M, as judged by the appearance of transformed 'fast' form on native PAGE; generation of bands of approximately 90 kDa on reduced SDS-PAGE and formation of covalent complexes enzyme-inhibitor on SDS-PAGE. On the other hand, the total proteolytic activity on azocasein dropped significantly in the presence of alpha 2-M, although partial activity was still maintained. The proteinases detected as a double band of 44 and 53 kDa on gelatin SDS-PAGE were also inhibited by alpha 2-M. Results suggest that the study of specific interactions between alpha 2-M and T. cruzi-proteinases, probably with cruzipain, could be biologically important in the fate of T. cruzi-infection and Chagas' disease.
authors.affiliation: Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina. gustavo@bioclin.uncor.edu.ar
authors.forename: A
authors.initials: A
authors.lastname: Ramos
authors.forename: M S
authors.initials: MS
authors.lastname: Remedi
authors.forename: C
authors.initials: C
authors.lastname: Sánchez
authors.forename: G
authors.initials: G
authors.lastname: Bonacci
authors.forename: M A
authors.initials: MA
authors.lastname: Vides
authors.forename: G
authors.initials: G
authors.lastname: Chiabrando
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D007976:Leupeptins / Q000494:pharmacology; D011480:Protease Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D013997:Time Factors; D014105:Tosyl Compounds / Q000494:pharmacology; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000201:enzymology*; D000511:alpha-Macroglobulins / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D007976:Leupeptins; D011480:Protease Inhibitors; D014105:Tosyl Compounds; D000511:alpha-Macroglobulins; C003614:4-toluenesulfonyl fluoride; D010450:Endopeptidases; C032854:leupeptin