Revelation of Acyl Double Bond Positions on Fatty Acyl Coenzyme A Esters by MALDI/TOF Mass Spectrometry

Hay Yan J. Wang, Fong Fu Hsu

Research output: Contribution to journalArticlepeer-review

Abstract

Fatty acyl coenzyme A esters (FA-CoAs) are important crossroad intermediates in lipid catabolism and anabolism, and the structures are complicated. Several mass spectrometric approaches have been previously described to elucidate their structures. However, a direct mass spectrometric approach toward a complete identification of the molecule, including the location of unsaturated bond(s) in the fatty acid chain has not been reported. In this study, we applied a simple MALDI/TOF mass spectrometric method to a near-complete characterization of long-chain FA-CoAs, including the location(s) of the double bond in the fatty acyl chain, and the common structural features that recognize FA-CoAs. Negative ion mass spectra of saturated, monounsaturated, and polyunsaturated FA-CoAs were acquired with a MALDI/TOF mass spectrometer using 2,5-dihydroxybenzoic acid as the matrix and ionized with a laser fluence two folds of the threshold to induce the in-source fragmentation (ISF) of the analytes. The resulting ISF spectra contained fragment ions arising from specific cleavages of the C-C bond immediate adjacent to the acyl double-bond. This structural feature affords locating the double-bond position(s) of the fatty acyl substituent. Thereby, positional isomer such as 18:3(n - 3) and 18:3(n - 6) FA-CoA can be differentiated without applying tandem mass spectrometry.

Original languageEnglish
Pages (from-to)1047-1057
Number of pages11
JournalJournal of the American Society for Mass Spectrometry
Volume31
Issue number5
DOIs
StatePublished - May 6 2020
Externally publishedYes

Keywords

  • acyl double-bond position
  • fatty acyl coenzyme A ester
  • in-source fragmentation
  • MALDI/TOF

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