Biosynthesis of paf-acether. XVI. Acetyltransferase specificity determines composition of paf-acether molecular species in human polymorphonuclear neutrophils.
In human neutrophils, the velocity of the lyso paf-acether:acetyl-CoA acetyltransferase reaction was almost 2-fold higher in the presence of lyso paf-acether bearing a 16:0 alkyl chain at the sn-1 position of glycerol than in that of its 18:0 analog. The paf-acether produced from an equimolar mixture of the two substrates was a 5:1 mixture, respectively, of the 16:0 and 18:0 species. The ratio of 16:0/18:0 lyso paf-acether in microsomal fractions, as analyzed by gas chromatography, was close to 1, whereas the paf-acether formed in these fractions from endogenous phospholipids was nearly exclusively of the 16:0 form. We conclude that acetyltransferase possesses a higher affinity for 16:0 than for 18:0 lyso-PAF and thus might control the molecular composition of paf-acether synthesized by stimulated human polymorphonuclear neutrophils.
Ninio
E
E
INSERM U.200, Université Paris-Sud, Clamart, France.
Bessou
G
G
D000101:Acetyl-CoA C-Acetyltransferase / Q000378:metabolism*; D002849:Chromatography, Gas; D006801:Humans; D008861:Microsomes / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D010972:Platelet Activating Factor / Q000096:biosynthesis*
D010743:Phospholipids; D010972:Platelet Activating Factor; D000101:Acetyl-CoA C-Acetyltransferase