Oscillations in the phosphofructokinase-fructose 1,6-bisphosphatase cycle. I. Purification and kinetic characterization of fructose 1,6-bisphosphatase from pig liver

Abstract

A rapid and effective purification procedure for pig liver fructose 1,6-bisphosphatase in neutral form is described. The procedure involves heat treatment and chromatography with CM-Sephadex with specific elution of the enzyme by fructose 1,6-bisphosphate and AMP. The enzyme was found suitable for integration into a reconstituted enzyme system in which the generation of oscillations is investigated. The kinetic properties of fructose 1,6-bisphosphatase are studied under conditions compatible to those applied for the investigation of the dynamic behaviour of the reconstituted system (pH 6.6, presence of inorganic phosphate). The enzyme is significantly inhibited by AMP and fructose 6-phosphate. The substrate fructose 1,6-bis phosphate has a high affinity to the enzyme and was found weakly inhibiting even at high concentrations. The kinetic results are interpreted in terms of a mathematical model which reflects the interaction of the various effectors with the enzyme.