KN-93 Phosphate

KN-93 (phosphate) is a potent and selective inhibitor of Ca²⁺/calmodulin-dependent kinase II (CaMKII) (K_i = 370 nM), inhibiting both the α- and β-subunits of CaMKII. It does not have significant effects on cAMP-dependent protein kinase, Ca²⁺/phospholipid-dependent protein kinase, myosin light chain kinase, or Ca²⁺ phosphodiesterase activity. It inhibits histamine-induced aminopyrine uptake in parietal cells (IC₅₀ = 300 nM). KN-93 can block voltage-gated potassium (K_v) channels when applied extracellularly, independent of its CaMKII action. More recently, KN-93 has been used to implicate roles for CaMKII in Ca²⁺-induced Ca²⁺ release in cardiac myocytes, constitutive phosphorylation of 5-lipoxygenase in 3T3 cells, and Ca²⁺-dependent activation of HIF-1α in colon cancer cells.

KN 93 Phosphate is a potent and selective inhibitor of Ca2+/calmodulin-dependent protein kinase II.