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Acyl-GPC and alkenyl/alkyl-GPC:acyl-CoA acyltransferases
P C Choy1, M Skrzypczak, D Lee
1Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Biochimica Et Biophysica Acta
|November 25, 1997
Summary
Choline-containing phospholipids, like phosphatidylcholine, are remodeled by deacylation-reacylation. Acyltransferases play a key role in determining the final molecular composition of these essential lipids.
Area of Science:
- Biochemistry
- Cell Biology
- Lipid Metabolism
Background:
- Phosphatidylcholine (GPC) is the most abundant choline phospholipid in mammalian tissues.
- Plasmenylcholine (1-alkenyl-2-acyl-GPC) and alkyl-GPC are significant in specific cell types and tissues.
- Acyl group distribution in phospholipids is asymmetric, with unsaturated fatty acids typically at the sn-2 position.
Purpose of the Study:
- To investigate the enzymatic mechanisms, specifically acyltransferases, involved in remodeling choline-containing phospholipids.
- To understand the factors influencing the molecular species composition of phosphatidylcholine, plasmenylcholine, and alkyl-GPC.
- To characterize different forms of acyltransferases and their substrate specificities.
Main Methods:
- Studied deacylation-reacylation processes in various mammalian tissues.
- Investigated the activity and localization of 1-acyl-GPC:acyl-CoA acyltransferase and 1-alkenyl-GPC acyltransferase.
- Identified a novel 1-alkenyl-GPC acyltransferase in guinea pig heart mitochondria.
- Examined acyltransferase specificity towards polyunsaturated acyl groups and acyl-CoA.
Main Results:
- Demonstrated the deacylation-reacylation pathway for remodeling the sn-2 acyl group of phosphatidylcholine.
- Microsomal acyltransferases show specificity for polyunsaturated acyl groups.
- A distinct 1-alkenyl-GPC acyltransferase was found in guinea pig heart mitochondria.
- The contribution of acyltransferases to the final phospholipid composition is not fully defined.
Conclusions:
- Acyltransferases are crucial for determining the molecular species composition of choline-containing phospholipids.
- Enzyme specificity, substrate flux, and acyl-CoA pool size are key factors in phospholipid remodeling.
- Further research is needed to fully elucidate the role of acyltransferases in vivo.