Figure 9. CK2 phosphorylation does not stimulate Cdc34-ubiquitin charging activity of a His₆-Cdc34-Δ12 protein.

(A) Recombinant His₆-Cdc34 and His₆-Cdc34-Δ12, either phosphorylated in vitro by CK2 or not, were incubated with E1, ATP and biotinylated ubiquitin. Samples were taken at the indicated time points. Data are representative of one of three experiments performed. (B) Recombinant His₆-Cdc34 was treated as in (A) except that DTT (200 mM) was added to protein samples prior to electrophoresis.