Stereoisomers of C6-Cer, their metabolism, and their biological activity
| Stereoisomer | Structure | Metabolism to GlcCer1-a | Activity in ceramide-mediated signaling pathways1-b |
|---|---|---|---|
| d-erythro-Cer (2S, 3R) | +++ | +++ | |
| l-erythro-Cer (2R, 3S) | +++ | ++ | |
| d-threo-Cer (2R, 3R) | − | + | |
| l-threo-Cer (2S, 3S) | − | ++++ | |
| d-erythro-dihydroCer (2S, 3R) | + | − | |
The structures of the four stereoisomers of C6-Cer and the structure of C6-d-erythro-dihydroCer are shown, along with the R/S nomenclature for clarification. The sphingoid long chain base is indicated by R. The extent of metabolism of the stereoisomers to C6-GlcCer and their activities in ceramide-mediated signaling pathways are taken from published data.
↵F1-a Pagano and Martin (1988); Paul et al. (1996).
↵F1-b The activity of the ceramide stereoisomers in signaling pathways was determined for C2-ceramides (Bielawska et al., 1993; Fishbein et al., 1993).