1977 Volume 30 Issue 6 Pages 500-505
Four DNA-dependent RNA-polymerases were separated from the cell homogenate of mouse Leukemia L1210 cells 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 α-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.