Ethanolamine kinase catalyzes the first step in phosphatidylethanolamine (PtdEtn) biosynthesis via the CDP-Etn pathway. The deduced 452-amino acid protein has a calculated molecular mass of 49.7 kD.
contains a region rich in hydrophobic residues and a putative transmembrane helix. In transfected cells, however, EKI1 associated with the cytosolic fraction rather than the membrane fraction. Northern blot analysis detected a 2.2-kb EKI1 transcript in all tissues examined and an additional 1.7-kb EKI1 transcript in testis.EKI1 had negligible choline kinase activity in vitro, and overexpression did not influence phosphatidylcholine biosynthesis. Acceleration of the CDP-Etn pathway did not change the rate of PtdEtn formation via decarboxylation of phosphatidylserine