choline/ethanolaminephosphotransferase 1 (hCEPT1, CEPT1)

Function

• catalyzes both phosphatidylcholine & phosphatidylethanolamine biosynthesis from CDP-choline & CDP-ethanolamine, respectively
• role in protein-dependent process of phospholipid transport to distribute phosphatidyl choline to the lumenal surface
• higher cholinephosphotransferase activity than ethanolaminephosphotransferase activity

CDP-ethanolamine + 1,2-diacylglycerol
           <-->
CMP + phosphatidylethanolamine

CDP-choline + 1,2-diacylglycerol
          <-->
CMP + phosphatidylcholine

Cofactor: Mg+2, Mn+2

Kinetic parameters:

• KM=37 uM for CDP-choline
• KM=101 uM for CDP-ethanolamine
• Vmax=10.5 nmol/min/mg enzyme with CDP-choline as substrate
• Vmax=4.35 nmol/min/mg enzyme with CDP-ethanolamine as substrate

Structure

• belongs to the CDP-alcohol phosphatidyltransferase class-I family

Compartment

• endoplasmic reticulum membrane
• nuclear membrane

Expression

ubiquitously expressed

More general terms

• transmembrane 8 protein
• phosphotransferase
• glycoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q9Y6K0.html