Abstract
A supernatant initiation factor from Krebs II ascites cells required for the initiation of translation of encephalomyocarditis virus RNA has been purified to homogeneity. The purification process involves (NH4)2SO4 fractionation followed by chromatography on hydroxyapatite, DEAE‐Sephadex A‐50, Sephadex G‐100 superfine and phosphocellulose. The molecular weight of the factor is about 53000 as determined by dodecylsulfate‐polyacrylamide‐disc‐gel electrophoresis.