The CDP-ethanolamine route: the same three steps as for choline
Route: Ethanolamine → Phosphoethanolamine → CDP-ethanolamine + 1,2-Dipalmitoyl-sn-glycerol (diacylglycerol) → 1,2-Dipalmitoylglycero-3-phosphoethanolamine (phosphatidylethanolamine)
Phosphatidylethanolamine is the major phospholipid of the inner leaflet of cell membranes. To activate the alcohol, ethanolamine is first phosphorylated by ATP to phosphoethanolamine. This reacts with CTP to form CDP-ethanolamine and releases pyrophosphate. The phosphoethanolamine unit of CDP-ethanolamine is then transferred to a diacylglycerol to give phosphatidylethanolamine and CMP. The kinase card shows a choline/ethanolamine kinase and the last card shows choline/ethanolamine phosphotransferase 1 (CEPT1), which makes both phosphatidylethanolamine and phosphatidylcholine. The drawings show palmitoyl on both acyl positions as a stand-in. The drawing of phosphatidylethanolamine leaves the glycerol center unspecified.
Practice this pathway All pathways
| Step | Enzyme | EC | In | Out |
|---|---|---|---|---|
| 1 | Choline/ethanolamine kinase beta | 2.7.1.82 | ATP | ADP |
| 2 | CTP:phosphoethanolamine cytidylyltransferase | 2.7.7.14 | CTP | PPᵢ |
| 3 | Choline/ethanolamine phosphotransferase 1 | 2.7.8.1 | CMP |
Build any of these from its atoms.
Enzyme names and EC numbers are those used on the interactive board. Checked against sources: see the claim table in the repository (tools/pathway_data/checks).