title: Interaction of non-phosphorylated liver pyruvate kinase with fructose 1,6-bisphosphate and peptides that mimic the phosphorylatable N-terminus of the enzyme.
abstract: The interaction of non-phosphorylated L-type pyruvate kinase (L-PK) with fructose 1,6-bisphosphate (FBP), which is an allosteric activator of the phosphorylated enzyme, and peptides that mimic the phosphorylatable N-terminal regulatory domain of the enzyme, was studied. It was found that the catalytic activity of the enzyme was not enhanced in the presence of FBP, and this ligand acted as a relatively weak reversible inhibitor of the enzyme activity in the micromolar concentration range. The phosphorylation site analogue peptides RRASVA and RRAAVA had no effect on the activity of the enzyme, while the phosphorylated peptide RRAS(Pi)VA reversibly inhibited the enzyme and this process was characterised by the Ki value 47 μM. As the phosphorylated form of L-PK is a subject of significant allosteric regulation by FBP, it was concluded that phosphorylation should function as a molecular switch of the allosteric properties of this enzyme.
authors.affiliation: Institute of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia. ilony@ut.ee.
authors.forename: Ilona
authors.initials: I
authors.lastname: Faustova
authors.forename: Jaak
authors.initials: J
authors.lastname: Järv
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D005632:Fructose / Q000737:chemistry*; D005635:Fructosediphosphates / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D008099:Liver / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011770:Pyruvate Kinase / Q000737:chemistry*; D011817:Rabbits; D051381:Rats
chemical_list: D005635:Fructosediphosphates; D008024:Ligands; D010455:Peptides; D005632:Fructose; D011770:Pyruvate Kinase; C029063:fructose-1,6-diphosphate