Recombinant type I regulatory subunit of the cAMP-dependent protein kinase is biologically active

The cDNA for the porcine type I regulatory subunit (RI) of the cAMP-dependent protein kinase (cAMP-PK) was cloned into two different bacterial expression vectors: pKK223 and pUC18. Recombinant RI was produced by bacteria transformed with either construct, and purified by affinity chromatography. Both the native RI from the pKK223 construct and the RI with an amino terminal extension of eight amino acids from the pUC18 construct were found to be completely native with regard to inhibition of the catalytic subunit activity and cAMP binding.