The effect of lipids on the enzymatic activity of 6-phosphofructo-1-kinase from B. stearothermophilus

Maria-Nefeli Tsaloglou, George S. Attard, Marcus Dymond

Research output: Contribution to journalArticle

Abstract

6-Phosphofructo-1-kinase (PFK-1), a major regulatory enzyme in the glycolysis pathway, is a cytoplasmic enzyme with complicated allosteric kinetics. Here we investigate the effects of lipids on the activity of PFK from Bacillus stearothermophilus (BsPFK), to determine whether BsPFK shares any of the membrane binding or lipid binding properties reported for some mammalian PFKs. Our results show that large unilamellar vesicles (LUVs) composed of either the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or of 1:1 (mole ratio) DOPC and the fatty acid, oleic acid (OA), cause a three-fold increase in Vmax, depending on the lipid concentration and vesicle composition, but no change in Km. Further studies show lipids do not reverse the allosteric inhibitory effects of phosphoenolpyruvate (PEP) on BsPFK. SDS/PAGE studies do not show significant binding of the BsPFK tetramer to the surface of the phospholipid vesicles, suggesting that modulation of catalytic activity is due to binding of lipid monomers. By simulating the kinetics of BsPFK interaction with vesicles and lipid monomers we conclude that the change in BsPFK catalytic activity with respect to lipid concentration is consistent with monomer abstraction from vesicles rather than direct uptake of lipid monomers from solution.
Original languageEnglish
Pages (from-to)713-721
Number of pages9
JournalChemistry and Physics of Lipids
Volume164
Issue number8
DOIs
Publication statusPublished - 30 Nov 2011

Keywords

  • Bacillus stearothermophilus
  • Phosphofructokinase
  • Lipid-protein interactions
  • Glycolysis

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