An accurate and versatile method for determining the acyl group-introducing position of lysophospholipid acyltransferases

Biochim Biophys Acta Mol Cell Biol Lipids. 2019 Jul;1864(7):1053-1060. doi: 10.1016/j.bbalip.2019.02.008. Epub 2019 Mar 7.

Abstract

Lysophospholipid acyltransferases (LPLATs) incorporate a fatty acid into the hydroxyl group of lysophospholipids (LPLs) and are critical for determining the fatty acid composition of phospholipids. Previous studies have focused mainly on their molecular identification and their substrate specificity regarding the polar head groups and acyl-CoAs. However, little is known about the positional specificity of the hydroxyl group of the glycerol backbone (sn-2 or sn-1) at which LPLATs introduce a fatty acid. This is mainly due to the instability of LPLs used as an acceptor, especially for LPLs with a fatty acid at the sn-2 position of the glycerol backbone (sn-2-LPLs), which are essential for the enzymatic assay to determine the positional specificity. In this study, we established a method to determine the positional specificity of LPLAT by preparing stable sn-2-LPLs in combination with PLA2 digestion, and applied the method for determining the positional specificity of several LPLATs including LPCAT1, LYCAT and LPCAT3. We found that LPCAT1 introduced palmitic acid both at the sn-1 and sn-2 positions of palmitoyl-LPC, while LYCAT and LPCAT3 specifically introduced stearic acid at the sn-1 position of LPG and arachidonic acid at the sn-2 position of LPC, respectively. The present method for evaluating the positional specificity could also be used for biochemical characterization of other LPLATs.

Keywords: LPCAT1; LPCAT3; LYCAT; Lysophospholipid acyltransferase; Phospholipid; sn-1-Acyl lysophospholipid; sn-2-Acyl lysophospholipid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Acylglycerophosphocholine O-Acyltransferase / metabolism
  • Acyltransferases / metabolism*
  • Binding Sites
  • Fatty Acids / metabolism*
  • Glycerol / metabolism
  • Lysophospholipids / metabolism*
  • Methods
  • Palmitic Acid / metabolism
  • Stearic Acids / metabolism
  • Substrate Specificity

Substances

  • Fatty Acids
  • Lysophospholipids
  • Stearic Acids
  • Palmitic Acid
  • stearic acid
  • Acyltransferases
  • 1-Acylglycerophosphocholine O-Acyltransferase
  • LPCAT3 protein, human
  • Lpcat1 protein, human
  • Glycerol