Incorporation of arachidonic acid into 1-acyl-2-lyso-sn-glycero-3-phosphocholine of the human neutrophil

Floyd H. Chilton, Jean S. Hadley, Robert C. Murphy

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

In this study, the initial incorporation of arachidonic acid into human neutrophils has been examined. Neutrophils pulse labeled for 5 min with [3H]arachidonic acid rapidly incorporated this fatty acid into 1,2-diacylglycerophosphocholine. However, when neutrophils were pulse labeled with [3H]arachidonic acid for 5 min, washed, and allowed to incubate for an additional 120 min, the relative amount of [3H]arachidonic acid increased in alkylacylglycerophosphocholine molecular species. Similar, when neutrophils were pulse labeled, washed, and allowed to incubate in the presence of 30 μM unlabeled arachidonic acid for 120 min, [3H]arachidonic acid was also remodeled into alkylacylglycerophospocholine. These results implied that the initial incorporation of [3H]arachidonic acid proceeded via a free fatty acid intermediate into 1,2-diacyl-GPC, while the subsequent remodeling of arachidonate-containing glycerophospholipids did not. This initial incorporation was further investigated in a number of cell-free systems. Disrupted neutrophils incubated with [14C]arachidonoyl-CoA incorporated [14C]arachidonic acid into 1,2-diacyl-GPC containing 16:0, 18:0, and 18:1 at their sn-1 position in a pattern similar to that seen when whole neutrophils were incubated with arachidonic acid for 5 min. A small percentage of [14C]arachidonate from [14C]arachidonoyl-CoA was incorporated into 1-alkyl-2-acyl-GPC. The enzymatic activity responsible was found predominately in the membrane fraction of the broken cell preparation. This selectivity of the CoA-dependent acyltransferase for 1-acyl-linked glycerophosphocholine was further examined by adding [14C]arachidonoyl-CoA and various 1-radyl-2-lyso-GPC to neutrophil membrane preparations. These studies provide evidence that the initial incorporation of arachidonic acid into sn-glycero-3-phosphocholine takes place by an arachidonoyl-CoA: lysophosphatidylcholine acyltransferase(s) which is selective for the 1-acyl-2-lyso-GPC.

Original languageEnglish (US)
Pages (from-to)48-56
Number of pages9
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume917
Issue number1
DOIs
StatePublished - Jan 13 1987
Externally publishedYes

Keywords

  • 1,2-Diacyl-GPC
  • 1-Acyl-2-lyso-GPC
  • 1-O-Alkyl-2-acyl-GPC
  • Arachidonic acid
  • Arachidonoyl-CoA
  • Molecular species
  • Neutrophil
  • lysophosphatidylcholine acyltransferase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Endocrinology

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