Specificity of the in vitro interaction of methylfurfural with DNA.

Methylfurfural (MF) or 5-methyl 2-furaldehyde is a dietary mutagen and is present in various food products and beverages. Alkaline unwinding of calf thymus DNA and the protection of cleavage sites in lambda phage DNA from the action of various restriction enzymes was used to study the interaction of MF with DNA. Alkaline unwinding experiments showed the formation of an increasing number of strand breaks in duplex DNA, both with increasing MF concentration and time of reaction. Treatment of lambda phage DNA with MF protected cleavage with restriction endonucleases EcoRI and EcoRI* but not with SmaI and HaeIII. These results indicate that under the conditions used MF reacts exclusively with AT base pairs. A minimum of three to four consecutive AT base pairs is required for this reaction. This was determined by the use of restriction enzymes whose hexanucleotide recognition sequences contain subsets of AT base pairs. Indirect evidence further indicates that modification (possibly alkylation) of DNA bases and phosphates may also occur.