Cdk/Crk Inhibitor is a cell-permeable pyrazolo-pyrimidinone compound that acts as a potent, selective, and ATP-competitive inhibitor of Cdks (IC50 = 48 nM, 15 nM, 9 nM, 10 nM, 71 nM, and 9 nM for Cdc2 (Cdk1)/cyclin B, Cdk2/cyclin E, Cdk3/cyclin E, Cdk5/p35, Cdk7/cyclin H/MAT1, and Cdk9, respectively). It inhibits Cdk4/cyclin D1, Cdk6/cyclin D3, and GSK-3β only at much higher concentrations (IC50 = 839 nM, 282 nM, and 754 nM, respectively) and exhibits little activity towards a panel of 60 other kinases. Cdk/Crk Inhibitor is a broad-spectrum growth inhibitor toward tumor cells, but not non-transformed quiescent fibroblasts.
