A transacylation reaction initiates PAF biosynthesis in the remodeling pathway

Conference · Mon Mar 11 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5312149

Uemura, Y; Lee, T C; Snyder, F ^[1]

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1. Oak Ridge Associated Univ., TN (United States)

The remodeling pathway for the biosynthesis of platelet activating factor (PAF) consists of the following reaction sequence: alkylacyl-glycerophosphocholine (GPC) {endash}> lyso-PAF{endash}> PAF. In this investigation, the authors describe a novel transacylase activity that generates the lyso-PAF intermediate which can then be acetylated to form PAF. Alkyllysoglycerophosphoethanolamine (GPE), acyllyso-GPE, alk-1-enyllyso-GPE, unlabeled lyso-PAF, acyllyso-GPC and alk-1-enyllyso-GPC are all able to stimulate the formation of ({sup 3}H)lyso-PAF from a ({sup 3}H)alkylacyl-GPC precursor pool associated with HL-60 cell (granulocytic) membranes. Other glycerolipids with free hydroxyl groups, cholesterol, phosphatidylcholine, and phosphatidylethanolamine had no stimulatory effect on the release of ({sup 3}H)lyso-PAF from the prelabeled membranes under identical conditions. The transacylase responsible for the release of lyso-PAF from the membrane-associated alkylacyl-GPC is not affected by Ca{sup 2+}, EGTA, or a known phospholipase A{sub 2} inhibitor, p-bromophenacyl bromide. The observed transacylase reaction is directly coupled to PAF production since the addition of alk-1-enyllyso-GPE to HL-60 membranes in the presence of ({sup 14}C)acetyl-CoA stimulates PAF formation.

• DOE Contract Number: AC05-76OR00033
• OSTI ID: 5312149
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:4
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ACYLATION
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
GROWTH FACTORS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MEMBRANES
MITOGENS
ORGANIC COMPOUNDS
PROTEINS
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS