Autocamtide-2 is a highly selective peptide substrate for calcium/calmodulin-dependent protein kinase II (CaMKII), which belongs to the CAMK Ser/Thr protein kinase family. The sequence derives from the Thr-286 autophosphorylation site of the alpha subunit of CaMKII. Autocamtide-2 contains the R-X-X-S/T consensus site surrounded by basic residues for improved binding to phosphocellulose. CaMKII is a prominent kinase in the central nervous system that functions in long-term potentiation and neurotransmitter release. Autophosphorylation of Thr-286 allows the kinase to switch from a calmodulin-dependent to a calmodulin-independent state. CaMKII phosphorylates Autocamtide-2 with a Km of 2 uM whereas protein kinase C (PKC) has a Km > 50 uM and protein kinase A (PKA) has no activity.