Different susceptibility of alkylacyl--versus diacyl--and alkenylacyl--phosphatidylcholine subclasses to stimulation of biosynthesis by phospholipase C.
Krebs II ascites cells were incubated with [3H] or [14C] choline in the presence or in the absence of Clostridium welchii phospholipase C (PLC). At enzyme concentrations where cell lysis remained limited, PLC specifically enhanced phosphatidylcholine (PC) biosynthesis, as shown by comparison with [14C] ethanolamine. Further analysis revealed that the stimulating effect of PLC remained limited to 1,2-diacyl-sn-glycero-3-phosphocholine (diacyl-GPC) and 1-alkenyl-2-acyl-GPC, whereas the biosynthesis of 1-alkyl-2-acyl-GPC, the putative precursor of platelet activating factor (PAF-acether) remained unchanged. These differences reflect different localizations of the three PC subclasses in the plasma membrane and are discussed in relation to the regulation mechanism of PC biosynthesis.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D051379:Mice; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D010740:Phospholipases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism*
D010713:Phosphatidylcholines; D010740:Phospholipases; D010738:Type C Phospholipases; D002794:Choline