Alpha-tocopheryl phosphate: a novel, natural form of vitamin E.
We have detected alpha-tocopheryl phosphate in biological tissues including liver and adipose tissue, as well as in a variety of foods, suggesting a ubiquitous presence in animal and plant tissue. Alpha-tocopheryl phosphate is a water-soluble molecule that is resistant to both acid and alkaline hydrolysis, making it undetectable using standard assays for vitamin E. A new method was therefore developed to allow the extraction of both alpha-tocopheryl phosphate and alpha-tocopherol from a single specimen. We used ESMS to detect endogenous alpha-tocopheryl phosphate in biological samples that also contained alpha-tocopherol. Due to the significance of these findings, further proof was required to unequivocally demonstrate the presence of endogenous alpha-tocopheryl phosphate in biological samples. Four independent methods of analysis were examined: HPLC, LCMS, LCMS/MS, and GCMS. Alpha-tocopherol phosphate was identified in all instances by comparison between standard alpha-tocopheryl phosphate and extracts of biological tissues. The results show that alpha-tocopheryl phosphate is a natural form of vitamin E. The discovery of endogenous alpha-tocopheryl phosphate has implications for the expanding knowledge of the roles of alpha-tocopherol in biological systems.
Gianello
Robert
R
Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Australia.
Libinaki
Roksan
R
Azzi
Angelo
A
Gavin
Paul D
PD
Negis
Yesim
Y
Zingg
Jean-Marc
JM
Holt
Phillip
P
Keah
Hooi-Hong
HH
Griffey
Annike
A
Smallridge
Andrew
A
West
Simon M
SM
Ogru
Esra
E
D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D021241:Spectrometry, Mass, Electrospray Ionization; D014810:Vitamin E / Q000302:isolation & purification*; D024502:alpha-Tocopherol / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000378:metabolism
D014810:Vitamin E; C012552:alpha-tocopherol phosphate; D024502:alpha-Tocopherol