This peptide is a potent calmodulin antagonist and an inhibitor for calcium/calmodulin-dependent protein kinase II (CaMKII), which belongs to the CAMK Ser/Thr protein kinase family. The sequence derives from the residues 290-309 within the calmodulin-binding domain of human CaMKII alpha. CaMKII is a prominent kinase in the central nervous system that functions in long-term potentiation and neurotransmitter release. This peptide inhibits CaMKII activation by blocking calmodulin binding to CaMKII.Leu-Lys-Lys-Phe-Asn-Ala-Arg-Arg-Lys-Leu-Lys-Gly-Ala-Ile-Leu-Thr-Thr-Met-Leu-Ala or LKKFNARRKLKGAILTTMLA