Cell-permeable. A selective CDK 1 inhibitor (Cdk1/B1 and Cdk1/A). Arrests cell cycle at G1, S, and G2/M and induces apoptosis in embryonic stem cells. Actively enhances downstream p53 signaling to promote apoptosis in AML cell lines, and suppresses phosphorylation of p53 at Ser315 and procaspase-8 at Ser387.