Multiple DNA-dependent RNA polymerases in Trypanosoma cruzi.

DNA-dependant RNA polymerase solubilized from cultured Trypanosoma cruzi epimastigotes was chromatographed on A-25 Sephadex and gave a single peak of activity. Subsequent phosphocellulose chromatography revealed two peaks of RNA polymerase activity. These peaks have different sensitivities to the toxin alpha-amanitin. The first peak is 50% inhibited by 17.8 micrograms ml-1 amanitin while the second peak is 50% inhibited by an amanitin concentration of 44.6 micrograms ml-1. The activity of both peaks is blocked by actinomycin D, but is unaffected by rifampicin. Each peak is stimulated by Mn2+, and is optimal with single stranded DNA as a template.