<p>Choline kinase, (ATP:choline phosphotransferase, <db_xref db="EC" dbkey="2.7.1.32"/>) belongs to the choline/ethanolamine kinase family.</p><p>Ethanolamine and choline are major membrane phospholipids, in the form of glycerophosphoethanolamine and glycerophosphocholine. Ethanolamine is also a component of the glycosylphosphatidylinositol (GPI) anchor, which is necessary for cell-surface protein attachment [<cite idref="PUB00044597"/>]. The de novo synthesis of these phospholipids begins with the creation of phosphoethanolamine and phosphocholine by ethanolamine and choline kinases in the first step of the CDP-ethanolamine pathway [<cite idref="PUB00044598"/>, <cite idref="PUB00003038"/>]. There are two putative choline/ethanolamine kinases (C/EKs) in the <taxon tax_id="5691">Trypanosoma brucei</taxon> genome. </p><p>Ethanolamine kinase has no choline kinase activity [<cite idref="PUB00044597"/>] and its activity is inhibited by ADP [<cite idref="PUB00003038"/>]. Inositol supplementation represses ethanolamine kinase, decreasing the incorporation of ethanolamine into the CDP-ethanolamine pathway and into phosphatidylethanolamine and phosphatidylcholine [<cite idref="PUB00044599"/>]. </p>