Inhibitory effects of human alpha 2-macroglobulin on Trypanosoma cruzi epimastigote proteinases

• Published in: Acta tropica Vol. 68; no. 3; pp. 327 - 337
• Main Authors: Ramos, A, Remedi, M S, Sánchez, C, Bonacci, G, Vides, M A, Chiabrando, G
• Format: Journal Article
• Language: English
• Published: Netherlands 01-12-1997
• Subjects: alpha-Macroglobulins - metabolism; alpha-Macroglobulins - pharmacology; Animals; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Endopeptidases - drug effects; Endopeptidases - isolation & purification; Endopeptidases - metabolism; Leupeptins - pharmacology; Protease Inhibitors - metabolism; Protease Inhibitors - pharmacology; Time Factors; Tosyl Compounds - pharmacology; Trypanosoma cruzi - drug effects; Trypanosoma cruzi - enzymology
• ISSN: 0001-706X
• DOI: 10.1016/S0001-706X(97)00110-1

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.