Open AccessTotal structure characterization of unsaturated acidic phospholipids provided by vicinal di-hydroxylation of fatty acid double bonds and negative electrospray ionization mass spectrometry
Author(s) -
Morten K. Moe,
Trude Anderssen,
Morten B. Strøm,
Einar Jensen
Publication year - 2005
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2004.09.014
Subject(s) - chemistry , electrospray ionization , mass spectrometry , tandem mass spectrometry , phosphatidic acid , phosphatidylglycerol , chromatography , hydroxylation , electrospray , organic chemistry , stereochemistry , phosphatidylcholine , phospholipid , biochemistry , membrane , enzyme
In the present work, the unsaturated fatty acid substituents of some phosphatidic acid, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol species were converted to their 1,2-di-hydroxy derivatives by OsO(4). The subsequent electrospray ionization tandem low-energy mass spectrometry analysis of the deprotonated species allowed positional determination of the double bonds by the production of specific product-ions. The product-ions are formed by charge-remote and charge-proximate homolytic cleavages as well as charge-directed heterolytic cleavages and rearrangements. The commercial availability of pure species of the phospholipids in question was limited, and a number of species were therefore synthesized. The developed method was used to fully characterize the two isobaric phosphatidylglycerol species 16:0/16:1Delta(9) and 16:0/16:1Delta(10) extracted from the bacteria Methylococcus capsulatus. The presence of these fatty acids was supported by a gas-chromatography mass spectrometry investigation of the dimethyloxazoline derivatives of the species of the lipid extract. The present work demonstrates that a total structure characterization of acidic unsaturated phospholipids in isolate or in mixtures is accomplished by vicinal di-hydroxylation of olefinic sites and subsequent electrospray ionization mass spectrometry of the derivatized phospholipids.