[Partial purification and characterization of nuclear DNA-topoisomerases from trypanosomes (author's transl)]

We have prepared an extract presenting two types of topoisomerase activity from a nuclear fraction of Trypanosoma cruzi. The first one was revealed by the relaxation of supercoiled DNA molecules and was independent of ATP. Mg++ enhanced the reaction, without being necessary. Activity was observed between pH 5.4 and pH 8.5. The second activity was revealed by the formation of catenated molecules in the presence of ATP.