5-hydroxydopa, a new compound in the Raper-Mason scheme of melanogenesis

Oxidation of tyrosine or dopa by tyrosinase leads to the formation of 5-OH-dopa, a compound previously unknown in melanogenesis. 5-OH-dopa, first detected as an unknown compound on HPLC of the dopa-tyrosinase incubate, was purified by Al2O3-adsorption, semipreparative HPLC, and ion-exchange chromatography. 5-OH-dopa was identified by comparison with the authentic compound in several chromatographic systems, by electrochemical oxidation studies and by mass spectrometry.