Cell-permeable. A potent inhibitor of CDK1/cyclin B (IC₅₀ = 400 nM), CDK2/cyclin A (IC₅₀ = 680nM) , CDK5 (IC₅₀ = 850nM) and with much less effect other kinases. In addition, it has been found to be a useful GSK-3β inhibitor (IC₅₀ = 23nM). More recently, kenpaullone has been shown to increase neurogenesis of human neural progenitor cells through stimulation of Wnt/β-catenin signaling pathway.