CHOLINE KINASE FROM YEAST

Choline kinase, the initial enzyme of the CDP-choline pathway, mediate s the conversion of choline to phosphorylcholine and is localized in t he supernatant fraction of cells. The enzyme also catalyzes the phosph orylation of ethanolamine, functioning as the initial enzyme of the CD P-ethanolamine pathway as well. Yeast choline kinase is encoded by a s ingle structural gene, CKI, which was cloned by the genetic complement ation of the choline kinase mutation cki. The deduced sequence compris es 582 amino acid residues with a molecular mass of 66316 Da and bears local sequence similarity to various protein kinases and bacterial an tibiotic phosphotransferases. The expression of yeast choline kinase i s transcriptionally repressed by myo-inositol and choline in a coordin ate manner with other phospholipid-synthesizing enzymes in yeast. (C) 1997 Elsevier Science B.V.