Calmodulin from bovine brain

Ca²⁺ binding protein that is required for activation of cyclic nucleotide-dependent phosphodiesterase. It is also a cofactor/activator of nitric oxide synthase, calcineurin, and many kinases including ATPase, myosin light chain kinase, and CAM kinase I, II, and III. It mediates ryanodine receptor activation by cyclic ADP ribose and is involved in intracellular Ca²⁺ homeostasis.

Calmodulin is the Ca⁺² dependent regulator protein (CDR), troponin C-like protein.

One unit will stimulate 0.008 activated unit of phosphodiesterase, 3′:5′-cyclic nucleotide in a 3 ml reaction volume at pH 7.5 and 30 °C, to 50% of the maximum activity of the enzyme when saturated with activator, in the presence of 0.01 mM Ca²⁺.