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Identification of abundant alkyl ether glycerophospholipids in the human lens by tandem mass spectrometry techniques

Journal Article


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Abstract


  • Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our knowledge have not previously been observed in human tissue. Isomeric 1-O-alk-1'-enyl ethers were absent or in low abundance. Examination of the double bond position within the phospholipids using OzID revealed that several positional isomers were present, including sites of unsaturation at the n-9, n-7, and even n-5 positions. Tandem CID/OzID experiments revealed a preference for double bonds in the n-7 position of 1-O-ether linked chains, while n-9 double bonds predominated in the ester-linked fatty acids [e.g., GPEtn(11Z-18:1e/9Z-18:1) and GPSer(11Z-18:1e/9Z-18:1)]. Different combinations of these double bond positional isomers within chains at the sn-1 and sn-2 positions point to a remarkable molecular diversity of ether-lipids within the human lens.

UOW Authors


  •   Deeley, Jane M. (external author)
  •   Thomas, Michael C. (external author)
  •   Truscott, Roger
  •   Mitchell, Todd
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2009

Citation


  • Deeley, J., Thomas, M., Truscott, R. J.W., Mitchell, T. W. & Blanksby, S. J. (2009). Identification of abundant alkyl ether glycerophospholipids in the human lens by tandem mass spectrometry techniques. Analytical Chemistry, 81 (5), 1920-1930.

Scopus Eid


  • 2-s2.0-64749085047

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1321&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/287

Number Of Pages


  • 10

Start Page


  • 1920

End Page


  • 1930

Volume


  • 81

Issue


  • 5

Abstract


  • Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our knowledge have not previously been observed in human tissue. Isomeric 1-O-alk-1'-enyl ethers were absent or in low abundance. Examination of the double bond position within the phospholipids using OzID revealed that several positional isomers were present, including sites of unsaturation at the n-9, n-7, and even n-5 positions. Tandem CID/OzID experiments revealed a preference for double bonds in the n-7 position of 1-O-ether linked chains, while n-9 double bonds predominated in the ester-linked fatty acids [e.g., GPEtn(11Z-18:1e/9Z-18:1) and GPSer(11Z-18:1e/9Z-18:1)]. Different combinations of these double bond positional isomers within chains at the sn-1 and sn-2 positions point to a remarkable molecular diversity of ether-lipids within the human lens.

UOW Authors


  •   Deeley, Jane M. (external author)
  •   Thomas, Michael C. (external author)
  •   Truscott, Roger
  •   Mitchell, Todd
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2009

Citation


  • Deeley, J., Thomas, M., Truscott, R. J.W., Mitchell, T. W. & Blanksby, S. J. (2009). Identification of abundant alkyl ether glycerophospholipids in the human lens by tandem mass spectrometry techniques. Analytical Chemistry, 81 (5), 1920-1930.

Scopus Eid


  • 2-s2.0-64749085047

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1321&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/287

Number Of Pages


  • 10

Start Page


  • 1920

End Page


  • 1930

Volume


  • 81

Issue


  • 5