Fractionation and structural elucidation of the active components of aurintricarboxylic acid, a potent inhibitor of protein nucleic acid interactions.

Commercially available, as well as synthetically prepared, samples of aurintricarboxylic acid (a widely employed potent inhibitor of protein nucleic acid interactions) consist mostly of a heterogeneous collection of polymers, as shown by fractionation schemes utilizing both dialysis and ultrafiltration, and by molecular weight measurements. 13C-NMR studies suggest that the polymeric material is of the phenol-formaldehyde type; inhibitory assays that depend on the formation of a protein-nucleic acid complex revealed that potency varied directly with the molecular weight of the polymer. Fractions of molecular weight 400 were essentially inactive.