title: Melanogenesis from 5-hydroxytryptamine, 5,6- and 5,7-dihydroxytryptamines. An in vitro study using MALDI-TOF.
abstract: The role of tyrosinase and peroxidase in melanogenesis of 5-hydroxytryptamine, 5,6- and 5,7-dihydroxytryptamines was investigated by matrix-assisted laser desorption/ionization mass spectrometry. Each enzyme was incubated with the tryptamine derivatives and samples were drawn at various times, ultrafiltered and immediately lyophilized. The results indicated that peroxidase promotes oligomerization of 5-HT with fast kinetics but with yields lower than those achieved by tyrosinase. 5,6- and 5,7-DHT formed low molecular mass oligomers in the presence of peroxidase alone. The addition of hydrogen peroxide evidences different reactivity of the two isomers: 5,6-DHT formed immediately a black precipitate while oligomers of the molecule itself and of its oxidation products were detectable for 5,7-DHT.
authors.affiliation: Department of Pharmaceutical Sciences, University of Padova, Italy. bertazzo@dsfarm.unipd.it
authors.forename: A
authors.initials: A
authors.lastname: Bertazzo
authors.forename: D
authors.initials: D
authors.lastname: Favretto
authors.forename: C V
authors.initials: CV
authors.lastname: Costa
authors.forename: G
authors.initials: G
authors.lastname: Allegri
authors.forename: P
authors.initials: P
authors.lastname: Traldi
mesh_terms: D015115:5,6-Dihydroxytryptamine / Q000737:chemistry*; D015116:5,7-Dihydroxytryptamine / Q000737:chemistry*; D006735:Horseradish Peroxidase; D006861:Hydrogen Peroxide; D007202:Indicators and Reagents; D008543:Melanins / Q000737:chemistry*; D014442:Monophenol Monooxygenase; D012701:Serotonin / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: D007202:Indicators and Reagents; D008543:Melanins; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D014442:Monophenol Monooxygenase; D015115:5,6-Dihydroxytryptamine