Cdk / Crk抑制剂是一种细胞可渗透的吡唑并嘧啶酮化合物，可作为Cdks的有效，选择性和ATP竞争性抑制剂（IC | 50 | = 48 nM，15 nM，9 nM，10 nM，71 nM和Cdc2（Cdk1）/细胞周期蛋白B，Cdk2 /细胞周期蛋白E，Cdk3 /细胞周期蛋白E，Cdk5 / p35，Cdk7 /细胞周期蛋白H / MAT1和Cdk9分别为9 nM。它仅在高得多的浓度（分别为IC | 50 | = 839 nM，282 nM和754 nM）下抑制Cdk4 / cyclin D1，C Cdk/Crk Inhibitor is a cell-permeable pyrazolo-pyrimidinone compound that acts as a potent, selective, and ATP-competitive inhibitor of Cdks (IC|50|= 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 (IC|50|= 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.