Restriction patterns of model DNA treated with 5,6-dihydroxyindole, a potent cytotoxic intermediate of melanin synthesis: effect of u.v. irradiation

Abstract

The interaction of 5,6-dihydroxyindole, a putative cytotoxic intermediate of melanin synthesis, with model λ phage DNA has been investigated by using type II restriction endonucleases and CsCI buoyant density centrifugation. As evidenced by agarose gel electrophoresis and density gradient profiles, the 5,6-dihydroxyindole or u.v. treated DNAs, restricted or not, are modified. U.v. irradiation enhances 5,6-dihydroxyindole binding to DNA, but no sequence specific binding was observed. The action of L-3,4-dihydroxyphenyl-alanine on the restriction patterns of λ phage DNA was also investigated and the effect appeared smaller, by qualitative evaluation, than that produced by 5,6-dihydroxyindole.