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Alk‐1‐enylacyl, alkylacyl, and diacyl subclasses of native ethanolamine and choline glycerophospholipids can be quantified directly by phosphorus‐31 NMR in solution
Author(s) -
Malewicz Barbara,
Baumann Wolfgang J.
Publication year - 1996
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02524294
Subject(s) - glycerophospholipids , glycerophospholipid , ethanolamine , chemistry , phospholipid , degree of unsaturation , nuclear magnetic resonance spectroscopy , choline , chromatography , tetramethylammonium , stereochemistry , biochemistry , organic chemistry , ion , membrane
Abstract We show that phosphorus‐31 nuclear magnetic resonance spectroscopy can be used to distinguish and to quantify the alk‐1‐enylacyl, alkylacyl, and diacyl glycerophosphoethanolamine (GPE) subclasses, and the respective glycerophosphocholine (GPC) subclasses, in their native form without prior degradation or derivatization, provided the phospholipids are observed in the nonaggregated state. Monomeric phospholipid distribution is ascertained by recording the spectra, after removal of metal ions, on CDCI 3 /CD 3 OD/D 2 O (50∶50∶15, by vol) solutions. The utility of this approach is exemplified for the ethanolamine glycerophospholipids (EPL) from bovine brain and the choline glycerophospholipids (CPL) from bovine heart. Sharp and well‐resolved resonances are obtained for alkylacylGPE (+0.395 ppm; re 1% H 3 PO 4 ), alkenylacylGPE (+0.353 ppm), and diacylGPE (+0.315 ppm), and for alkylacylGPC (−0.383 ppm), alkenylacylGPC (−0.436 ppm) and diacylGPC (−0.451 ppm). Integrated peak reas are shown to closely correlate with dose. Accurate quantitation of EPL and CPL subclasses at submicromolar levels can further be facilitated by use of synthetic dialkylGPE (+0.602 ppm) and dialkylGPC (−0.196 ppm) as internal standards. The method is simple, rapid, sensitive and reproducible, and permits the complete resolution and direct quantitation of all ethanolamine and choline glycerophospholipid subclasses quite independent of fatty chain length and degree of unsaturation.