KS 501

KS 501 is a potent and selective calmodulin inhibitor. KS 501 inhibits the activation of calmodulin kinase I and II, but has less effect against cyclic adenosine 3’,5’-monophosphate (cyclic AMP)-sensitive kinase. KS 501 inhibits the enzyme through interfering with calmodulin activation rather than through a direct effect on the enzyme. KS 501 can be used for the study of leukemia^[1]. In Vitro:KS 501 (0-100 μM) inhibits calmodulin-sensitive phosphodiesterase activity in a concentration-dependent manner (IC₅₀ = 0.8 μM)^[1].
KS 501 (0.25-2 μM) shows a decreasing inhibitory effect on phosphodiesterase activity as the concentration of calmodulin increases^[1].
KS 501 (10-40 μM) inhibits calmodulin-dependent synapsin I phosphorylation at 40 μM, while 10 μM has no inhibitory effect on basal activity and instead causes slight stimulation^[1].
KS 501 (10-40 μM) inhibits the phosphorylation of synapsin I at site 1 (a substrate of calmodulin kinase I) and sites 2 and 3 (a substrate of calmodulin kinase II)^[1].
KS 501 (10-40 μM) only partially inhibits synapsin I phosphorylation of cAMP-sensitive protein kinase (PKA)^[1].
KS 501 (0-120 μM) inhibits the proliferation of L1210/S cells (IC₅₀ = 80 μM)^[1].