Figure 3.

Inhibition of cyclin-ubiquitin ligation by C→S mutants of human UbcH10 and clam E2-C. (A) All incubations contained 0.25 μM wild-type clam E2-C. Where indicated, increasing concentrations of recombinant, purified C→S mutants of human UbcH10 (○) or clam E2-C (•) were added. Cyclin-ubiquitin ligation was assayed as described in the text. (B) Recombinant, purified human UbcH10 was added at the concentrations indicated in the absence (○, Control) or presence (•) of human UbcH10 C→S mutant (1 μM).