On RNA-polymerases of leukemia L1210 origin and an enzymatic method to screen antitumor antibiotics.

Four DNA-dependent RNA-polymerases were separated from the cell homogenate of moust leukemia L1210 cell by DEAE-cellulose column chromatography and tentatively designated as Peaks I, II, III and IV in the elution order. Peak II was inactivated by the addition of alpha-amanitin and effects of antibiotics and enzymes on the RNA-polymerase activity using Peaks, I, II and a mixture of Peaks I and II were examined. The RNA-polymerases were used to screen for enzyme inhibitors produced by microbes. This enzymatic method was successfully proved to select antitumor antibiotics.