Figure 4.

Cyclin-dependent kinase specific activity in breast cancer xenograft tissues. Previously untreated tumor-bearing mice were given a single 20-mg/kg dose of paclitaxel. Tumor tissues were resected 24 hours later, lysed, immunoprecipitated with (a) anti-cyclin-dependent kinase (CDK) 1 antibody or (b) anti-CDK2 antibody, and assayed for kinase activity. Histone H1 was used as the substrate. U, units.