title: Investigation of the molecular structure of the human stratum corneum ceramides [NP] and [EOS] by mass spectrometry.
abstract: The aim of this study was to characterize the two ceramide (CER) subclasses CER[NP] and CER[EOS] of human stratum corneum and to identify the chemical structures of their subspecies. High-performance thin-layer chromatography and normal-phase high-performance liquid chromatography were used for the separation of CER fractions, whereas nanoelectrospray ionization tandem mass spectrometry was applied to investigate the chemical structures in detail. Thus, CER[EOS] fragmentation revealed that in addition to linoleic acid other esterified fatty acids occur in the ω-position. Of particular interest is the identification of a 17:2 fatty acid located in this part of the molecule. Several subspecies of CER[NP], including subspecies with odd numbers of carbon atoms in both chains, the non-α-hydroxylated fatty acid moiety (part N) and the phytosphingosine (part P), were identified. Furthermore, it was found that 12% of CER[NP] subspecies have an odd number of carbon atoms in both chains of the molecule. Similar results were obtained for CER[EOS]. Both the esterified fatty acid (part E) and the sphingosine base (part S) were found to contain odd-numbered chain lengths. These results underline the heterogeneity of the CER composition in the stratum corneum lipid bilayer.
authors.affiliation: Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany.
authors.forename: A
authors.initials: A
authors.lastname: Hinder
authors.forename: C E H
authors.initials: CE
authors.lastname: Schmelzer
authors.forename: A V
authors.initials: AV
authors.lastname: Rawlings
authors.forename: R H H
authors.initials: RH
authors.lastname: Neubert
mesh_terms: D002518:Ceramides / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005227:Fatty Acids / Q000737:chemistry*; D006801:Humans; D012867:Skin / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013110:Sphingosine / Q000031:analogs & derivatives / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D002518:Ceramides; D005227:Fatty Acids; C012491:phytosphingosine; D013110:Sphingosine