Production of melanin pigments by cytochrome c/H2O2 system.
In the presence of hydrogen peroxide cytochrome c can perform the oxidation of catecholamines and their S-cysteinyl-derivatives yielding melanins as final products. The initial reaction rate is linearly dependent on cytochrome c and H2O2 concentration; the reaction follows the Michaelis and Menten kinetics both for H2O2 and hydrogen donors. Sulfhydryl 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.
Department of Biochemical Sciences A. Rossi Fanelli, University La Sapienza of Rome, Italy. marosei@axrma.uniroma1.it
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D000818:Animals; D002395:Catecholamines / Q000737:chemistry* / Q000378:metabolism; D003574:Cytochrome c Group / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008543:Melanins / Q000096:biosynthesis / Q000737:chemistry*; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction
D002395:Catecholamines; D003574:Cytochrome c Group; D008543:Melanins; D006861:Hydrogen Peroxide; D014442:Monophenol Monooxygenase