Characterization and optimization of phospholipase A2 catalyzed synthesis of phosphatidylcholine

Research output: Contribution to journalArticle

Abstract

The phospholipase A2 (PLA2) catalyzed synthesis and hydrolysis of phosphatidylcholine (PC) was studied in a water activity controlled organic medium. The aim of the study was to find the conditions most favorable for the synthetic reaction. To do this, the impact of various parameters such as water activity, substrate concentration and temperature on enzyme activity and equilibrium yield was determined. The PC to lysophosphatidylcholine (LPC) ratio at equilibrium increases with decreasing water activity and increasing fatty acid concentration, as can be expected from the law of mass action of an esterification reaction. The enzyme activity on the other hand decreases under conditions that favor the esterification. The best yield in the synthetic reaction is 60% at a water activity of 0.11 and an oleic acid concentration of 1.8 M. That is to our knowledge the highest yield ever reported in this reaction. Both the hydrolysis and synthesis reaction follow Michaelis-Menten kinetics, the apparent K(m) values are the same for PC and LPC, namely 4.9 mM. V(max) is 82.5 and 10.4 nmol h-1 mg-1 for the hydrolysis and synthesis reaction, respectively. Studies on PLA2 at water activity controlled conditions resulted in a more complete understanding of the enzymatic reaction and allowed to find the conditions most favorable for the synthetic reaction.

Details

Authors
Organisations
External organisations
  • Lund University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biocatalysis and Enzyme Technology

Keywords

  • Equilibrium, Esterification, Organic solvent, Phosphatidylcholine, Phospholipase A, Water activity
Original languageEnglish
Pages (from-to)76-84
Number of pages9
JournalBiochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
Volume1343
Issue number1
Publication statusPublished - 1997 Nov 14
Publication categoryResearch
Peer-reviewedYes