IC50: 40 nM (CaMKII).
It is found that Autocamtide-2-related inhibitory peptide (a novel synthetic peptide ATP) is a potent inhibitor of CaM-kinase II with an IC 50 of 40 nM, which is active in the presence or absence of Ca 2+ /calmodulin. It is 50 and 500 times more potent than CaMK-(281-302Ala286) and KN-93,respectively, under the assay condition used.