Browsing by Subject "Extradiol"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    Embargo
    Characterization of recombinant Beta vulgaris 4,5-DOPA-extradiol-dioxygenase active in the biosynthesis of betalains
    (2012-01-24) Gandía-Herrero, Fernando; García-Carmona, Francisco; Bioquímica y Biología Molecular A
    Betalains are water-soluble pigments with high antiradical capacity which bestow bright colors to flowers, fruits and other parts of most plants of the order Caryophyllales. The formation of the structural unit of all betalains, betalamic acid from the precursor amino acid 4,5-dihydroxyphenylalanine is catalyzed by the enzyme 4,5-DOPAextradiol-dioxygenase followed by intramolecular cyclization of the 4,5-secodopa intermediate. This paper describes the purification and the molecular and functional characterization of an active 4,5-DOPA-extradiol-dioxygenase from the best-known source of betalains—Beta vulgaris—after heterologous expression in Escherichia coli. The enzyme is a monomeric protein with a molecular mass of 32 kDa characterized by chromatography, electrophoresis and MALDITOF analysis. Enzyme kinetic properties are characterized in the production of betalamic acid, the structural, chromophoric and bioactive unit of plant pigment betalains.
  • Thumbnail Image
    Publication
    Open Access
    Escherichia coli protein YgiD produces the structural unit of plant pigments betalains: characterization of a prokaryotic enzyme with DOPA-extradiol-dioxygenase activity
    (Springer, 2013-05-12) Gandía Herrero, Fernando; García Carmona, Francisco; Bioquímica y Biología Molecular "A"
    Betalamic acid is the structural unit of all the natural pigments betalains. These are nitrogen-containing water soluble compounds with high colorant and bioactive properties, characteristic of plants of the order Caryophyllales. The formation of betalamic acid from the precursor amino acid 3,4-dihydroxy-L-phenylalanine (L-DOPA) by the enzyme 4,5- DOPA-extradiol-dioxygenase was supposed to be restricted to plants of this order and two fungal species. Here, the first case of betalamic acid formation by an enzyme other than eukaryotes is reported with a homolog enzyme from Escherichia coli. The protein YgiD has been cloned, expressed, and purified to carry out its molecular and functional characterization. The enzyme was obtained as a monomeric active protein with a molecular mass of 32 kDa characterized by chromatography, electrophoresis, and MALDI-TOF analysis. Enzyme kinetic properties are characterized in the transformation of the relevant substrate L-DOPA. Reaction was analyzed spectrophotometrically and by HPLC-DAD, electrospray ionization mass spectrometry, and time-of-flight mass spectrometry