Linked Life Data

11202369

Source:http://linkedlifedata.com/resource/pubmed/id/11202369

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-2-1
pubmed:abstractText
The photophysical properties of all-trans-retinal (RAL) have been extensively studied because of the importance of the retinoids in the visual process. However, little information is available regarding the participation of RAL in photochemical transformations such as photoxidation. RAL is one of several native chromophores that have been suggested to act as photosensitizers of damage in the human retina, and this damage would likely occur through oxidative pathways. Time-resolved and steady state techniques have been used to examine the photoreactivity of RAL toward several suitable substrates. The lifetime of the RAL triplet excited state is observed to decrease with increasing concentration of the well-known electron and hydrogen atom donors, 2,3,5,6-tetramethyl-1,4-phenylenediamine (DAD), hydroquinone (HQ), methylhydroquinone (MHQ), 2,3-dimethylhydroquinone (DMHQ) and trimethylhydroquinone (TMHQ), although the bimolecular rate constants for the reaction are much less than that of diffusion controlled (2.9 x 10(7) M-1 s-1, 1.2 x 10(5) M-1 s-1, 1.2 x 10(5) M-1 s-1, 1.5 x 10(5) M-1 s-1 and 1.6 x 10(6) M-1 s-1, for DAD, HQ, MHQ, DMHQ and TMHQ, respectively). In the presence of the donors, new absorptions grow concomitant with the decay of the triplet excited state, and for DAD and TMHQ, the observed spectra are similar to the spectra of p-phenylenediamine and TMHQ radicals. Irradiation of RAL in argon-saturated methanol results in fairly efficient photobleaching of RAL and in the formation of two new compounds having absorption spectra that are shifted below 300 nm. Irradiation of RAL in argon-saturated acetonitrile also results in photobleaching of RAL, but the reaction proceeds at a slower rate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0031-8655
pubmed:author
pubmed:issnType
Print
pubmed:volume
73
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
71-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Studies of all-trans-retinal as a photooxidizing agent.
pubmed:affiliation
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't