IMMUNOCHEMICAL EVIDENCE FOR INTERACTION BETWEEN CHOLECYSTOKININ C-TERMINAL PEPTIDES AND THE PROTEIN INHIBITOR OF ADENOSINE 3', 5'-CYCLIC MONOPHOSPHATE DEPENDENT PROTEIN KINASE IN HOG TERMINAL BILE DUCTS

Abstract

The interaction of cholecystokinin (CCK) C-terminal peptides with the protein inhibitor (PK-I) of adenosine 3', 5'-cyclic monophosphate-dependent protein kinase (A-PK) was studied by immunoprecipitation using anti-PK-I antibody. The binding of CCK-4 peptide to PK-I was shown to be specific ; while CCK-4 enhanced precipitation of PK-I with antibody, it did not enhance precipitation of bovine serum albumin (BSA) by anti-BSA. The interaction of CCK-4 with PK-I is reversible and similar to that of urea but different from that of alkali. These results support the conclusion that CCK-C terminal peptides interact specifically with PK-I.