The understanding of the structure and function of cGMP-dependent protein kinase (cGMP kinase) has been hindered by the difficulty to obtain large quantities of functional enzyme. A recombinant baculovirus encoding bovine cGMP kinase la was constructed and purified. Infected insect cells synthesized large amounts of soluble and biologically active cGMP kinase Iα representing up to 10% of the total cell extract protein. The recombinant enzyme had an identical apparent molecular mass, cGMP affinity and kinase activity as the native bovine lung enzyme. The high-level expression of functional cGMP kinase Iα should provide an excellent tool to study further the structure and function of cGMP kinase.
