Description_x000D_ Packaging_x000D_ 5, 25 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ R547 is a potent and selective ATP-competitive inhibitor of Cyclin-Dependent Kinases (CDK) 1, 2 and 4 with Ki of 2 nM for CDK1/cyclin B, 3 nM for CDK2/cyclin E, and 1 nM for CDK4/cyclin D1. R547 is less potent for CDK7 and GSK3α/β, and inactive (Ki > 5,000 nmol/L) against a panel of >120 unrelated kinases. R547 was shown to inhibit retinoblastoma protein in tumor cells and xenografts and showed up to 95% tumor growth inhibition in the HCT116 human colorectal tumor xenograft model in nude mice.