Melanogenesis from 5-hydroxytryptamine, 5,6- and 5,7-dihydroxytryptamines. An in vitro study using MALDI-TOF.
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.
Bertazzo
A
A
Department of Pharmaceutical Sciences, University of Padova, Italy. bertazzo@dsfarm.unipd.it
Favretto
D
D
Costa
C V
CV
Allegri
G
G
Traldi
P
P
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
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