title: The isolation and characterization of differentially phosphorylated fractions of phosphofructokinase from rabbit skeletal muscle.
abstract: A preparation of phosphofructokinase from rabbit skeletal muscle is described which exploits the association-dissociation properties of the enzyme. Phosphofructokinase to prepared is partially phosphorylated and may be fractioned into three distinct species with sedimentation coefficients of 30 S, 18 S and 13 S by chromatography of agarose gels, hydroxyapatite or DEAE-cellulose. Measurements of alkali-labile phosphate content (phosphoserine and/or phosphothreonine) show that fractions consisting almost exclusively of 30-S species and fractions consisting predominantly of 18-S and 13-S species contain approximately 0.15 and 0.29 mol of phosphate per phosphofructokinase monomer (Mr = 80000) respectively. The results are interpreted in terms of at least two 13-S components which differ in their phosphate contents and also in their self-association properties. The possible significance of phosphorylation is discussed.
mesh_terms: D000818:Animals; D001665:Binding Sites; D005636:Fructosephosphates / Q000494:pharmacology; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D010732:Phosphofructokinase-1 / Q000302:isolation & purification / Q000378:metabolism; D010750:Phosphoproteins / Q000302:isolation & purification; D011485:Protein Binding; D011817:Rabbits
chemical_list: D005636:Fructosephosphates; D010750:Phosphoproteins; D010732:Phosphofructokinase-1