ASCORBIC-ACID INHIBITS COVALENT BINDING OF ENZYMATICALLY GENERATED 2-ACETYL-AMINOFLUORORENE-N-SULFATE TO DNA UNDER CONDITIONS IN WHICH IT INCREASES MUTAGENESIS IN SALMONELLA TA-1538

14C(Acetyl) N-hydroxy-2-acetylaminofluorene (NOH-2AAF) became covalently bound to DNA during the generation of the reactive N-sulfate ester. Elution of DNA digests from Sephadex LH-20 columns yielded two peaks of radioactivity (Fractions A and B). Fraction B appears to represent a NOH-2AAF-nucleoside adduct, while Fraction A seems to be more clearly related to protein covalent binding. Ascorbic acid decreased NOH-2AAF covalent binding to DNA by approximately 80%, whether total binding or Fraction B is considered. Since ascorbic acid addition increased mutagenesis twelve fold under these conditions, the role of free radicals in the noncovalent ascorbate-dependent increase in mutagenesis is considered. © 1979.