KN-93 hydrochloride is a cell-permeable, reversible and competitive calmodulin-dependent kinase type II ( CaMKII ) inhibitor with a K i of 370 nM.

After 2 days of KN-93 treatment, 95% of cells are arrested in G1. G1 arrest is reversible; 1 day after KN-93 release, a peak of cells had progressed into S and G2-M. In addition, KN-93 also blocks cell growth stimulated by basic fibroblast growth factor, platelet-derived growth factor-BB, and epidermal growth factor in NIH 3T3 fibroblasts [1]. KN-93 inhibits the H +, K + -ATPase activity but strongly dissipates the proton gradient formed in the gastric membrane vesicles and reduces the volume of luminal space [2]. KN-93 (0.5 μM) prevents increased LV developed pressure during action potential prolongation and early afterdepolarizations. Ca 2+ -independent CaM kinase activity is increased during early afterdepolarizations and this increase is prevented by KN-93 [3].