Linked Life Data

16519984

Source:http://linkedlifedata.com/resource/pubmed/id/16519984

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2006-8-7
pubmed:abstractText
Plant copper/quinone amine oxidases are homodimeric enzymes containing Cu(II) and a quinone derivative of a tyrosyl residue (2,4,5-trihydroxyphenylalanine, TPQ) as cofactors. These enzymes catalyze the oxidative deamination of primary amines by a classical ping-pong mechanism, i.e. two distinct half-reactions, enzyme reduction by substrate followed by its re-oxidation by molecular oxygen. In the first half-reaction two forms of the reduced TPQ have been observed, the colorless Cu(II)-aminoquinol and the yellow Cu(I)-semiquinolamine radical so that this enzyme may be referred to as a "protein-radical enzyme". The interaction of xenon, in aqueous solutions, with the copper/TPQ amine oxidase from lentil (Lens esculenta) seedlings has been investigated by NMR and optical spectroscopy. NMR data indicate that xenon binds to the protein. Under 10 atm gaseous xenon and in the absence of substrates more than 60% native enzyme is converted into Cu(I)-semiquinolamine radical species, showing for the first time that both monomers in the dimer can generate the radical. Under the same experimental conditions the copper-free lentil enzyme is able to generate an intermediate absorbing at about 360 nm, which is assigned to the product Schiff base quinolaldimine which, to the best of our knowledge, has never been observed during the catalytic mechanism of plant amine oxidases. A possible role of the lysine residue responsible for the formation of Cu(I)-semiquinolamine and quinolaldimine, is proposed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
827-35
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:16519984-Amine Oxidase (Copper-Containing), pubmed-meshheading:16519984-Benzoquinones, pubmed-meshheading:16519984-Catalysis, pubmed-meshheading:16519984-Chromatography, High Pressure Liquid, pubmed-meshheading:16519984-Copper, pubmed-meshheading:16519984-Lens Plant, pubmed-meshheading:16519984-Magnetic Resonance Spectroscopy, pubmed-meshheading:16519984-Models, Chemical, pubmed-meshheading:16519984-Molecular Structure, pubmed-meshheading:16519984-Oxidation-Reduction, pubmed-meshheading:16519984-Plant Proteins, pubmed-meshheading:16519984-Seedling, pubmed-meshheading:16519984-Spectrometry, Fluorescence, pubmed-meshheading:16519984-Spectrophotometry, pubmed-meshheading:16519984-Spectrophotometry, Ultraviolet, pubmed-meshheading:16519984-Xenon, pubmed-meshheading:16519984-Xenon Isotopes
pubmed:year
2006
pubmed:articleTitle
An unexpected formation of the spectroscopic Cu(I)-semiquinone radical by xenon-induced self-catalysis of a copper quinoprotein.
pubmed:affiliation
Department of Applied Sciences in Biosystems, University of Cagliari, 09042 Monserrato (CA), Cagliari, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't