Fluorophore-labeled ether lipids: substrates for enzymes of the platelet-activating factor cycle in peritoneal polymorphonuclear leukocytes.
Cell-free preparations of ionophore-stimulated peritoneal rat polymorphonuclear neutrophils (PMNs) incubated with 1-(N-dansyl-11-amino-1-undecyl)-sn-glycerol-3-phosphorylcholine (dansyllyso-PAF) converted this fluorescent lyso ether lipid into two different classes of products. In the absence of acetyl-CoA 1-(N-dansyl-11-amino-1-undecyl)-2-long chain acyl-sn-glycerol-3-phosphorylcholine (dansylalkyl-2-acyl-GPC) was the only identified new fluorescent phospholipid. In the presence of acetyl-CoA an additional new product, 1-(N-dansyl-11-amino-1-undecyl)-2-acetyl-sn-glycerol-3-phosphorylcholine (dansyl-PAF), was formed. The formation of dansyl-PAF in PMN homogenates was only transient with a maximum after about 4 min. When PMN homogenates were incubated with dansyl-PAF the formation of dansyllyso-PAF was observed prior to the formation of dansyl-2-acyl-GPC. Thus, our data indicate that enzymatically formed dansyl-PAF is completely remodeled into dansylalkyl-2-acyl-GPC by the sequential action of PAF acetylhydrolase and CoA-independent transacylase. These results demonstrate that peritoneal rat PMNs contain lyso-PAF acetyltransferase, PAF acetylhydrolase, and CoA-independent transacylase and that fluorophore-labeled ether lipids provide an easy means to assay enzymes which catalyze important enzymatic reactions involved in the biosynthesis and remodeling of platelet-activating factor.
Schindler
P W
PW
Pharma Forschung, Hoechst AG, Frankfurt, Federal Republic of Germany.
Walter
R
R
Hendrickson
H S
HS
D000818:Animals; D003619:Dansyl Compounds / Q000502:physiology*; D004987:Ethers; D007476:Ionophores / Q000494:pharmacology; D008055:Lipids; D009504:Neutrophils / Q000201:enzymology*; D010529:Peritoneal Cavity / Q000166:cytology; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000502:physiology*; D051381:Rats
D003619:Dansyl Compounds; D004987:Ethers; D007476:Ionophores; D008055:Lipids; D010972:Platelet Activating Factor; C058864:dansyl-platelet activating factor