## Abstract The activity of tyrosinase and peroxidase + H~2~O~2~ in promoting melanogenesis from tryptophan (Trp) and 7โhydroxytryptophan (7โHTP) has been investigated. The reaction samples have been drawn at different reaction times and analysed by MALDI mass spectrometry. The data obtained showe
An investigation on the possible role of melatonin in melanogenesis
โ Scribed by Andrea Rizzi; Stefano Comai; Antonella Bertazzo; Carlo V. L. Costa; Graziella Allegri; Pietro Traldi
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 445 KB
- Volume
- 41
- Category
- Article
- ISSN
- 1076-5174
- DOI
- 10.1002/jms.1010
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โฆ Synopsis
Abstract
The possible role of melatonin in melanogenesis was investigated by performing reactions of melatonin with peroxidase + H~2~O~2~ or H~2~O~2~ only, in the presence or absence of UV irradiation. Samples of the reaction mixtures were drawn at different times (from 15 to 480 min), the enzyme (when present) was removed by ultrafiltration and the samples so obtained were analyzed by MALDI/MS.
The results show that melatonin undergoes oligomerization reaction with peroxidase + H~2~O~2~, leading to heptameric species. For high reaction times the MALDI/MS data do not show the formation of larger oligomers, but UVโvis spectroscopy indicates that the oligomerization processes proceed. The failure of MALDIโTOF in the identification of larger oligomers was related to the chemicalโphysical and morphological behavior of melanins.
In the case of UV irradiation, the formation of species originating from the Oโ and O~2~ addition to melatonin, which activate new oligomerization channels, has been observed. Copyright ยฉ 2006 John Wiley & Sons, Ltd.
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