The reduction potential of the beta-carotene.+ /beta-carotene couple in an aqueous micro-heterogeneous environment.
There is a resurgence of interest in the role of electron transfer reactions involving beta-carotene in photosynthesis. There is also current debate on the health benefits of dietary carotenoids and the possible deleterious effects on certain sub-populations such as smokers. The impact of dietary carotenoids on health may well be also related to radical reactions. A key parameter in biological systems is therefore the one-electron reduction potential of the carotenoid radical cation, now reported for the first time in a model biological aqueous environment. The value obtained is 1.06+/-0. 01 V and is sufficiently high to oxidise cell membrane proteins, but is low enough to repair P(680).+ in the photosynthetic reaction centre.
Edge
R
R
School of Chemistry and Physics, Lennard-Jones Laboratories, Keele University, Keele, UK.
Land
E J
EJ
McGarvey
D J
DJ
Burke
M
M
Truscott
T G
TG
D002412:Cations / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism; D004579:Electron Transport; D005609:Free Radicals / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D016877:Oxidants / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins; D011675:Pulse Radiolysis; D019163:Reducing Agents / Q000378:metabolism*; D012996:Solutions; D013055:Spectrophotometry, Infrared; D013816:Thermodynamics; D014364:Tryptophan / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D014867:Water / Q000378:metabolism*; D019207:beta Carotene / Q000378:metabolism*
D002412:Cations; D005609:Free Radicals; D008823:Micelles; D016877:Oxidants; D045322:Photosynthetic Reaction Center Complex Proteins; D019163:Reducing Agents; D012996:Solutions; D019207:beta Carotene; D014867:Water; D014443:Tyrosine; D014364:Tryptophan; D003545:Cysteine