title: Zn2+-dependent reversible inactivation of rat liver phosphofructokinase-1. Purification of the inactivating protein and characterization of the inactivation reaction.
abstract: A protein has been purified from rat liver (about 5 mg from 100 g) which inactivates rat liver phosphofructokinase-1. According to dodecyl sulfate gel electrophoresis the protein consists of a single peptide chain with a Mr of 19,000. The inactivation of phosphofructokinase-1 by this protein results from a dissociation of phosphofructokinase-1 into its inactive protomers (Mr = 82,000). The inactivation is dependent on zinc ions in micromolar concentration (about 1-2 microM), but is inhibited by higher concentrations (greater than 50 microM). Fructose 1,6-bisphosphate as well as fructose 2,6-bisphosphate inhibit the inactivation reaction. In addition, both compounds as well as ATP can reverse the dissociation of phosphofructokinase-1. The phosphofructokinase-1 inactivating protein has no phosphatase activity with [32P]phosphofructokinase or low molecular weight phospho-compounds and does not possess any detectable proteolytic activity. It has the same affinity for the phospho- and the dephosphoform of phosphofructokinase-1, but preincubation of phosphofructokinase-1 with this inactivating protein reduces the maximum amount of phosphate incorporated into phosphofructokinase-1 and accelerates the velocity of the dephosphorylation reaction. A direct Zn2+-dependent binding of phosphofructokinase-1 to the inactivating protein has been demonstrated in experiments with matrix-bound phosphofructokinase-1 inactivating protein.
mesh_terms: D000818:Animals; D002413:Cations, Divalent; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors*; D010766:Phosphorylation; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D015032:Zinc / Q000494:pharmacology*
chemical_list: D002413:Cations, Divalent; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D011506:Proteins; C048633:Ptms protein, rat; D010732:Phosphofructokinase-1; D015032:Zinc