Ceramides phosphoethanolamines

Nikolova-Karakashian, M. Assays for the biosynthesis of sphingomyelin and ceramide phosphoethanolamine. Methods Enzymol. 2000, 311, 31-42. 

The choice of commercially available PEG-lipids is ultimately quite reduced. The mainly reported ones are the anionic polyethylene glycol-phosphoethanolamine (PEG-PE) and the neutral PEG-ceramide (Fig. 1). 

SIP lyase, a pyridoxal 5 -phosphate dependent enzyme that has a potential role in controlling cell fate and stress responses (96, 97), cleaves SIP between C-2 and C-3 to produce an a,P-unsaturated fatty aldehyde and phosphoethanolamine. Pyridoxal 5 -phosphate forms a Schiff base with the amino group of SIP. SIP lyase plays a role in determining the balance between the intracellular levels of SIP and ceramide. 

Sphingosine is catabolized to rrans-2-hexadecanal and phosphoethanolamine by way of sphingosine phosphate and its cleavage by a lyase. Catabolism of glycosphingolipids involves removal of successive glycosyl residues from their nonreducing end until ceramide is released. 

Fig. 1. The structure of GPI anchors. All characterized GPl anchors share a common core consisting of ethanol-amine-P04-6Man(al-2)Man(al 6)Man(al-4)GlcN(al-6)m) o-lno-l-P04-lipid. Heterogeneity in GPl anchors is derived from various substitutions of this core structure and are represented as R groups. R] and R2 may be long chain fatty acyl or alkyl groups or ceramide. R3 is frequently palmitate positioned at either C2 or C3 of the inositol ring. R4 and R7 are additional phosphoethanolamines. R5, R and Rg may be various glycan substitutions. The few known substituted glycan structures are indicated. (Redrawn from ref [18].)...

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