32P-postlabelling analysis of bulky aromatic adducts.

The 32P-postlabelling assay has emerged as a major tool for detecting DNA adducts induced by structurally diverse carcinogens, particularly bulky aromatics. The assay comprises enzymatic degradation of DNA to 3'-mononucleotides, enrichment of adducts, 5'-32P-labelling, adduct separation by TLC, and detection and quantitation of adducts. This report describes (1) an improved solvent extraction procedure for isolating DNA from tissues and (2) an up-dated version of the assay that we consider optimal for bulky adducts. The use of a non-urea solvent mixture (isopropanol: 4 M ammonium hydroxide) has been found to improve adduct separation and signal-to-noise ratios issues and (2) an up-dated version of the assay that we consider optimal for bulky adducts. The use of a non-urea solvent mixture (isopropanol: 4 M ammonium hydroxide) has been found to improve adduct separation and signal-to-noise ratios.