Effect of CrATP on the association of the reacting forms of yeast hexokinase.

Reacting enzyme sedimentation studies have been performed with yeast hexokinase isozymes A and B in the presence and absence of chromium ATP at pH 6.75. Preincubation of either isozyme with CrATP causes a shift in the monomer-dimer equilibrium toward the monomeric form. The results are consistent with the observed increase in inhibition caused by CrATP (Danenberg, K.D., and Cleland, W.W. (1975) Biochemistry 14, 28-39) being due to a conformational change in the protein which causes a decrease in the association constant for the monomer.