Isolation and properties of the replicase of encephalomyocarditis virus.

The RNA-dependent RNA polymerase (replicase) of encephalomyocarditis (EMC) virus was found to be closely associated with the smooth membranes of infected BHK-21 cells. An RNA-dependent EMC replicase was extracted from the membranes with 0.15% sodium dodecyl sulfate (SDS) and 1,1,2-trichlorotri-fluoroethane (Genetron 113) and further purified by high-salt dextran-polyethylene glycol phase separation, sievorptive chromatography, and glycerol gradient sedimentation. The enzyme does not manifest strict specificity toward EMC RNA template. It can use also Qbeta RNA, rRNA of BHK cells, or poly(C). SDS-polyacrylamide gel electrophoresis of purified EMC replicase labeled with radioactive methionine revealed that, of all the stable EMC proteins, the enzyme contains predominantly the 56,000-dalton (E) polypeptide.