Amino acid sequence of the catalytic subunit of bovine type II adenosine cyclic 3',5'-phosphate-dependent protein kinase

Abstract

The 350-residue amino acid sequence of the catalytic subunit of bovine cardiac muscle cAMP-dependent protein kinase is described. The protein has a MW of 40,862, which includes an N-tetradecanoyl (myristyl) group blocking the NH2 terminus and phosphate groups at threonine-197 and serine-338. Seven methionyl bonds in the S-carboxymethylated protein were cleaved with cyanogen bromide to yield 8 primary peptides. These fragments, and subpeptides generated by cleavage with trypsin, pepsin, chymotrypsin, thermolysin and Myxobacter AL-1 protease II, were purified and analyzed to yield the majority of the sequence. The primary peptides were aligned by analyses of overlapping peptides, particularly of methione-containing tryptic peptides generated after in vitro [14C]methyl exchange labeling of methionyl residues in the intact protein.