Pheomelanin production by the lipoxygenase-catalyzed oxidation of 5-S-cysteinyldopa and 5-S-cysteinyldopamine.
5-S-cysteinyl-dopa (cysdopa) and 5-S-cysteinyl-dopamine (cysdopamine) are oxidized in vitro by soybean lipoxygenase (LOX) in the presence of hydrogen peroxide giving rise to the corresponding pheomelanins. The reaction is activated by caffeic acid and other catechols, suggesting a cofactor role for these compounds. The activating effect is proportional to the concentration of the cofactor, with a saturation profile. The activation extent of the various cofactors is directly related to LOX affinity for the same compounds. The possible implications of the peroxidative action of LOX in Parkinson's disease and in aging are discussed.
Department of Biochemical Sciences, University of Rome La Sapienza, Italy.
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Foppoli
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Coccia
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Rosei
D002396:Catechols / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003548:Cysteinyldopa / Q000378:metabolism*; D004298:Dopamine / Q000031:analogs & derivatives* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D008084:Lipoxygenase / Q000378:metabolism*; D008543:Melanins / Q000096:biosynthesis*; D010084:Oxidation-Reduction
D002396:Catechols; D008543:Melanins; C018362:pheomelanin; D003548:Cysteinyldopa; C047408:5-S-cysteinyldopamine; D006861:Hydrogen Peroxide; D008084:Lipoxygenase; D004298:Dopamine