Linked Life Data

21323327

Source:http://linkedlifedata.com/resource/pubmed/id/21323327

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2011-3-3
pubmed:abstractText
Hydroxyl radical reacts readily with ?-carotene following submicrosecond laser photolysis of N-hydroxypyridine-2(1H)-thione (N-HPT) as a "photo-Fenton" reagent generating hydroxyl and thiyl radicals in acetonitrile:tetrahydrofuran (4:1, v/v) solution. On the basis of spectral evidence, and supported by kinetic considerations and thermodynamic calculations, a short-lived transient species, detected by time-resolved absorption spectroscopy with an absorption maximum at ?750 nm and a lifetime of ?150 ns at 25 °C under anaerobic conditions, is suggested to be the long-sought neutral ?-carotene radical formed by hydrogen-atom abstraction. The transient spectrum is different from the spectra of the ?-carotene radical cation (?1000 nm absorption maximum with a millisecond lifetime), the ?-carotene radical adducts (?520 nm, several microsecond lifetime), the ?-carotene radical cation ion pair (?750 nm, several hundred microsecond lifetime), and the ?-carotene radical anion (?880 nm, a few tens of microsecond lifetime). In parallel, ?-carotene reacts with the thiyl radical to yield a sulfur radical adduct with absorption maximum at ?520 nm with a lifetime of 3.0 ?s. For astaxanthin and canthaxanthin, the reaction with the thiyl radical dominates and the neutral radical is hardly formed in agreement with the less reducing properties of these 4,4'-diketo carotenoids without the reactive 4,4'-hydrogens.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1520-5207
pubmed:author
pubmed:copyrightInfo
© 2011 American Chemical Society
pubmed:issnType
Electronic
pubmed:day
10
pubmed:volume
115
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2082-9
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
Direct observation of the ?-carotene reaction with hydroxyl radical.
pubmed:affiliation
Department of Chemistry, Renmin University of China, Beijing, 100872.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't