Choline-phosphate cytidylyltransferase B (CCTβ)

Choline-phosphate cytidylyltransferase B (CCTβ), encoded by the **PCYT1B** gene, is an enzyme that catalyzes the rate-limiting step in the CDP-choline (Kennedy) pathway, which is essential for the biosynthesis of phosphatidylcholine, the major phospholipid in eukaryotic cell membranes[1][3][7]. CCTβ acts by converting CTP and phosphocholine into CDP-choline, a key intermediate in phospholipid metabolism and membrane formation[2]. This enzyme is one of two known isoforms in humans (the other being CCTα/PCYT1A). It is a member of the transferase family of enzymes and specifically the nucleotidyltransferases, and is classified under EC 2.7.7.15[2][5][7]. CCTβ is found primarily in the cytoplasm and is thought to provide cell-type–specific regulation of phosphatidylcholine biosynthesis[3][7]. Genetic variants or deficiencies in PCYT1B are associated with certain human developmental and lipid metabolism disorders[1][6]. No approved drugs, established pharmacological modulators, or documented biomarkers are currently cited for this isoform. There are no unique safety concerns or therapeutic challenges reported specifically for this enzyme.

Other names

phosphocholine cytidylyltransferase betaCCTBPCYT1BCTBCCT-βCTP:phosphocholine cytidylyltransferase betaCDP-choline synthetase betaCTP-phosphocholine cytidylyltransferase betaCDP-choline pyrophosphorylase beta