PRODUCTION OF MELANIN PIGMENTS BY CYTOCHROME-C H2O2 SYSTEM

In the presence of hydrogen peroxide cytochrome c can perform the oxid ation of catecholamines and their S-cysteinyl-derivatives yielding mel anins as final products. The initial reaction rate is linearly depende nt on cytochrome c and H2O2 concentration; the reaction follows the Mi chaelis and Menten kinetics both for H2O2 and hydrogen donors. Sulfhyd ryl compounds inhibit the formation of the pigment. The reported data indicate that a heme-containing protein belonging to the mitochondrial chain can accelerate the oxidation of catecholamines to eumelanins. ( C) 1998 Elsevier Science Ltd. All rights reserved.