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

RAMOS A, REMEDI MS, SÁNCHEZ C, BONACCI G, VIDES MA, CHIABRANDO G.

ELSEVIER SCIENCE BV

Año: 1997 vol. 68 p. 327 - 327

he inactivation of Trypanosoma cruzi proteinases by human alpha2-macroglobulin (alpha2-M), a major plasma proteinase inhibitor was studied. Evidences regarding the interaction between alpha2-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 alpha2-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 alpha2-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 alpha2-M. Results suggest that the study of specific interactions between alpha2-M and T. cruzi-proteinases, probably with cruzipain