The Effect of Magnesium on Some Physical Properties of Yeast Enolase

Abstract

Abstract It is shown by sedimentation velocity and polarization of fluorescence measurements that yeast enolase in solution becomes more compact on addition of magnesium. This is associated with changes in absorption, fluorescence emission, and fluorescence-polarization spectra, as well as in the thermal stability of the enzyme. Evidence is presented that this structural change is produced by the binding of 1 mole of metal per mole of protein. The dissociation constant, as determined by fluorimetric titrations, is 1.8 ± 0.5 x 10-6 m.