Figure 1. Reversibility of the CK2 subunit assembly in vitro.

(A) Exchange of CK2α in the subunit complex. Pre-formed complexes between immobilized MBP–CK2β and [³⁵S]methionine-labelled CK2α were incubated for 1 h with increasing concentrations of unlabelled CK2α. After washing, the amount of [³⁵S]methionine-labelled CK2α present in the complex was determined by radioactivity counting. (B) Kinetics of dissociation of the CK2 subunit complex. Pre-formed complexes between [³⁵S]methionine-labelled CK2α and MBP–CK2β were incubated for different times with a 10-fold molar excess of unlabelled CK2α. After washing, the amount of [³⁵S]methionine-labelled CK2α remaining in the complex was determined by radioactivity counting. Results are the means±S.D. (n=3).