Ceramides molecular species

Han X. Characterization and direct quantitation of ceramide molecular species from lipid extracts of biological samples by electrospray ionization tandem mass spectrometry. Anal. Biochem 2002 302 199-212. 

SLs are also polar cell membrane lipids, but they are typically present in much lower concentration than PLs. Soybeans are a relatively rich source of SLs (Vesper et al., 1999), and ceramides and cerebrosides are the primary SL classes in soybeans. SLs contain a sphingoid long-chain (CIS) drhydroxy base and an a-hydroxy fatty acyl chain that is linked to the base by an amide bond. The main soybean ceramide molecular species is a trihydroxy base (4-hydroxy-trans 8-sphingenine) V -acylated with a-hydroxy lignoceric acid (C24 0). The main soybean cerebroside molecular species is a dihydroxy base trans A-trans 8-sphingediene) V acylated with a-hydroxy palmitic acid. The general molecular structures of ceramide and cerebroside are shown in Fig. 10.4. 

In this paper, we have shown that this system can separate molecular species. One example is shown for cerebrosides (Fig. 3B). Human phospholipids and glycolipids have many forms (molecular species) because of the variation in fatty acids or ceramides. Phosphatidylcholine, sphingomyelin, and cerebroside are each reported to consist of more than 100 molecular species.As shown in Fig. 4, it is possible to obtain better resolution by changing the flow rate and the volumes of the fractions. Furthermore, better conditions can be optimized by changing the composition of the solvents to target one hpid, as shown. 

Kumagai, K., Yasuda, S., Okemoto, K., Nishijima, M., Kobayashi, S., and Hanada, K. CERT mediates intermembrane transfer of various molecular species of ceramides. J Biol Chem, 280, 2005, 6488-6495. 

Inositolphosphoryl ceramide-type sphingolipids were isolated from hyphal forms of C. albicans and three classes of molecules were fractionated by preparative HPLC on silica gel [65], Molecular species in each class differ in the composition of long chain bases and fatty acids the most abundant long chain bases were Cl8 and C20 phytosphingosines, while hydroxy and non-hydroxy C24, C25 and C26 were the most abundant fatty acids. The proposed structures, Ins-P-Cer, Man-Ins- P-Cer and Ins-P-Man-Ins-P-Cer, closely resemble the sphingolipids identified in S. cerevisiae [53],... 

Snada, S., Uchida, Y., Anraku, Y, Izawa, A., Iwamori, M., and Nagai, Y., Analysis of ceramide and monohexaosyl glycolipid derivatives by high-performance liquid chromatography and its application to the determination of the molecular species in tissues, J. Chromatogr., 400, 223-231, 1987. 

Karlsson, A.A., Amoldsson, K.C., Westerdahl, G., and Odham, G., Common molecular species of glucosyl ceramides, lactosyl ceramides and sphingomyelins in bovine milk determined by high-performance liquid chromatography-mass spectrometry, Milchwissenschaft, 52,554—559,1997. 

A variety of methods have been described for the separation of molecular species of sphingomyelin and glycosphingolipids. Silica gel TLC systems impregnated with sodium arsenite, sodium borate or silver nitrate have been used for different purposes. Most information is available on ceramide separations... 

Valeur et al (1994) elucidated the principal cleavage pathways of sphingomyelin in positive ion PSP. Sphingomyelin from bovine milk, bovine brain and chicken egg yolk were analysed by reversed-phase HPLC-PSP-MS. Spectra of individual molecular species showed prominent ceramide-derived fragment ions as well as ions of long-chain base (LCB) and carboxylic acid origin of the ceramide unit. 

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