the fact that the mutant was also defective in phosphorylcholine biosynthesis in vivo , together with the finding of an enzymatic lesion of the mutant in choline kinse in vitro as described above , clearly demonstrated that with respect to the reduced phosphatidylcholine biosynthesis the primary defect was at the level of choline kinase .
C0031716
phosphorylcholine
C0008405
choline