2022 Volume 6 Issue 2 Pages 101-111
Peroxisomes are subcellular organelles that are involved in various biological processes, including lipid synthesis and metabolism. Inherited dysfunctions of enzymes in the peroxisome cause a number of peroxisomal disorders associated with unusual lipid metabolites, as exemplified by X-linked adrenoleukodystrophy (X-ALD), the most prevalent peroxisomal disorder. Liquid chromatography linked to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is a pivotal technique for analysis of disease-specific metabolites to facilitate development of diagnostic markers and identification of disease-causing substances. Recent advances in MS have enabled intensive metabolomic targeting of very small amounts of lipids. However, it remains challenging to simultaneously analyze complex lipids such as glycosphingolipids. In addition, it is not easy to obtain stable isotopically labeled compounds for use as internal standards. Here, the application of LC-ESI-MS/MS in the analysis of phospholipids, glycosphingolipids (gangliosides, hexosylceramides, lactosylceramides, and globosides), and fatty acyl-coenzyme A is described. As an example, features of lipid species in X-ALD are described on the basis of the authors’ previous studies. A novel method for preparation of deuterated free fatty acids is also introduced, because deuterated compounds are useful as internal standards and probes for enzymes such as lysophospholipid acyltransferases that directly recognize a hydroxyoctadecadienoic acid (HODE) as an oxidized linoleic fatty acid.
