Sequence of two phosphorylated sites in the catalytic subunit of bovine cardiac muscle adenosine 3':5'-monophosphate-dependent protein kinase

J Biol Chem. 1979 Jul 25;254(14):6211-4.


The sequences of two phosphopeptides isolated from the catalytic subunit of bovine cardiac muscle cAMP-dependent protein kinase (type II) and from two of its cyanogen bromide fragments, have been determined. One phosphorylation site is a threonyl residue located approximately 180 residues from the blocked NH2 terminus. Its sequence is: -Gly-Arg-Thr-Trp-Thr(P)-Leu-Cys- and includes one of the three sulfhydryl groups present in the molecule. The second phosphorylated site within the sequence: -Val-Ser(P)-Ile-Asn- is located towards the carboxyl end of the protein where the other 2 cysteinyl residues also reside. The finding that phosphorylation of the catalytic subunit occurs on two discrete sites rather than at random suggests that it might be of physiological importance, e.g. in the regulation of enzyme activity.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Cattle
  • Cyclic AMP / pharmacology*
  • Macromolecular Substances
  • Myocardium / enzymology*
  • Phosphorylation
  • Protein Kinases* / metabolism


  • Macromolecular Substances
  • Cyclic AMP
  • Protein Kinases