Biocatalytic formation of synthetic melanin: The role of vanadium haloperoxidases, L-DOPA and iodide

Marisa Nicolai, Gisela Goncalves, Filipe Natalio, Madalena Humanes

Research output: Contribution to journalArticlepeer-review


The vanadium haloperoxidase (V-HPO) enzyme, extracted from the brown alga Laminaria saccharina, is able to catalyze the formation of a black precipitate, using as precursor the amino add L-dopa in the presence of hydrogen peroxide and iodide, in one-pot synthesis. The L-dopa oxidation is a multistep reaction with a crucial role played by the iodide in the enzyme catalyzed peroxidative production of dopachrome, a well known intermediate in the synthesis of melanin. Dopachrome is then converted to a synthetic form of melanin through a polymerization reaction. Factors, such as buffer composition and pH, influence significantly the reaction first steps, but further steps of melanin production are hardly influenced. The biosynthetic melanin produced through the combination V-HPO/1/H(2)O(2), was characterized by several spectroscopic techniques (UV-vis and FT-IR) as well as XRD. Moreover, this biopolymer is light sensitive, decomposing into oligo- and monomeric units. Scanning electron microscopy (SEM) imaging showed different morphologies when compared with commercial available melanin. The biosynthetic production of melanin can have a wide range of applications from photosensitive cells to biomedicine with the advantage of being produced under eco-friendly and mild conditions. (C) 2011 Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)887-893
Number of pages7
JournalJournal of Inorganic Biochemistry
Issue number6
StatePublished - Jun 2011

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Inorganic Chemistry


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