Abstract
The effect of some synthetic food dyes on RNA-synthesizing reaction was studied by employing the DNA-dependent RNA polymerase purified from Escherichia coli. And the modes of inhibition by ponceau 3R and rose bengale were discussed.
Ponceau 3R, ponceau R and orange I strongly inhibited the polymerase reaction at the concentration of 1mM. Among them, ponceau 3R was assumed to prevent the polymerase activity by interacting with the initiating region of RNA-transcription on DNA. The dye, however, showed a weak affinity to DNA.
Xanthene dyes which contained halogen atoms such as eosine, erythrosine, rose bengale and phloxine strongly inhibited the polymerase at 0.1mM. Since acid red showed no effect on the polymerase at higher concentrations, it was presumed that halogen molecule was essential to the inhibitory effect of xanthene dyes. The inhibition took place even in the dark, indicating no essential participation of photo-chemical reaction by these dyes. Rose bengale seemed to inhibit the RNA synthesis by binding with the polymerase molecule.
Naphthol yellow S and indigo carmine gave on inhibition for the polymerase reaction.
