A study on the amphiphilic proteins of three Trypanosoma cruzi populations.

1. Amphiphilic proteins were partially purified from culture-derived metacyclic trypomastigotes of the CL and Colombian strains and of the Dm 28c clone of T. cruzi by the use of Triton X-114. These proteins were subjected to one- and two-dimensional polyacrylamide electrophoresis in the presence of sodium dodecyl sulphate. 2. Relatively simple protein profiles with only 5 to 6 major bands were obtained. The CL and Colombian strains produced at least one additional major protein band (86 kDa) compared to the Dm 28c proteins. 3. Trypomastigote amphiphilic proteins displayed both electrophoretic mobilities and isoelectric points identical to those of two polypeptides precipitated by a rabbit antiserum which recognized metacyclic trypomastigote-specific surface antigens. 4. The partial purification of the T. cruzi amphiphilic proteins with Triton X-114 may provide a simple preparative step for the study of these differentiation-related polypeptides, as well as for the study of strain-specific (glyco)proteins and of their possible biological role.