PHOSPHATIDYLCHOLINE TRANSFER PROTEIN FROM BOVINE LIVER CONTAINS HIGHLY UNSATURATED PHOSPHATIDYLCHOLINE SPECIES

The phosphatidylcholine transfer protein (PC-TP) from bovine liver con tains one molecule of non-covalently bound PC, In order to gain more i nsight into the physiological function of PC-TP, PC was extracted from bovine liver PC-TP and its molecular species composition identified b y fast atom bombardment mass spectrometry, The prevailing molecular sp ecies were C18:0/C18:1-, C18:0/C18:2-, C18:0/C20:4-, C18:0/20:5- and C 18:0/C22:5-PC accounting for 85% of the PC species present, This molec ular species composition is not representative for what is present in bovine liver where these species account for 43% of the total PC conte nt [Montfoort et al, (1971) Biochim, Biophys, Acta 231, 335-342], Anot her striking observation is that PC species carrying a palmitoyl chain at the sn-1 position are nearly absent, despite these species being a bundantly present in bovine liver, This study suggests that PC-TP coul d play a role in the metabolism of highly unsaturated, stearoyl-contai ning PC species.