The self-association of rabbit muscle phosphofructokinase at pH 7.0 was investigated by velocity sedimentation. The process was demonstrated to be in a rapid, dynamic equilibrium. The concentration dependence of the weight-average sedimentation coefficient was monitored within the range of 10-750 μg/mL. The sedimentation properties of phosphofructokinase were analyzed by theoretical simulations for an associating system in rapid equilibrium. In the absence of any ligands and at a temperature of 23°C, the simplest computed model which gives the best fit between theoretical and experimental points can be described as progressive association of monomer ⇌ tetramer ⇌ 16-mer with apparent equilibrium constants K4 = 5.06 × 105 (mL/mg)3 and K16 = 3.25 × 1023 (mL/mg)15. However, at 5°C, the equilibrium was altered and can best be described as monomer ⇌ dimer ⇌ tetramer ⇌ 16-mer.
|Original language||English (US)|
|Number of pages||7|
|State||Published - 1981|
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