Syntide 2 is recognized as a substrate by Ca2+/calmodulin-dependent protein kinase II (CaMKII) with a Ki of 12 μM.
The sequence of syntide-2 (pro-leu-ala-arg-thr-leu-ser-val-ala-gly-leu-pro-gly-lys-lys) is homologous to phosphorylation site 2 in glycogen synthase. The relative Vmax/Km ratios of the known Ca2+-dependent protein kinases for syntide-2 are determined to be as follows: protein kinase II, 100; protein kinase C, 22; phosphorylase kinase, 2; myosin light chain kinase, 0.005[1].
[1]. Hashimoto Y, et al. Calcium . calmodulin-dependent protein kinase II and calcium . phospholipid-dependent protein kinase activities in rat tissues assayed with a synthetic peptide. Arch Biochem Biophys. 1987 Feb 1;252(2):418-25.