Possible genotoxicity of melanin synthesis intermediates: tyrosinase reaction products interact with DNA in vitro.

The actual cellular target of the cytotoxic intermediates of melanin synthesis is not yet known. In the present paper it is shown that eukaryotic DNA binds in vitro to soluble reaction products of tyrosinase (EC 1.14.18.1) and is physically modified, as ascertained by the following criteria: (a) buoyant density in cesium chloride density gradients; (b) polyacrylamide gel electrophoresis; (c) deoxyribonuclease (EC 3.1.4.5) test; (d) electron microscopy. The results reported here support the view that DNA itself may be a target for the cytotoxic intermediates of melanin synthesis.