title: ATP-citrate lyase. Structure of a tryptic peptide containing the phosphorylation site directed by glucagon and the cAMP-dependent protein kinase.
abstract: [32P]ATP-citrate lyase phosphorylated by the cAMP-dependent protein kinase was partially digested by trypsin. Two tryptic 32P-labeled phosphopeptides containing more than 90% of the 32P radioactivity present on the phosphorylated enzyme were purified and found to have overlapping amino acid sequences around the same phosphorylated site (Thr-Ala-Ser(32P)-Phe-Ser-Glu-Ser-Arg). Tryptic digestion of 32P-labeled ATP-citrate lyase purified from 32P-labeled hepatocytes exposed to glucagon yielded a major 32P-labeled peptide of identical amino acid composition with that indicated above. Thus, the site on ATP-citrate lyase phosphorylated by the cAMP-dependent protein kinase in vitro resides on the same octapeptide as the site of glucagon-stimulated phosphorylation in intact hepatocytes.
mesh_terms: D001275:ATP Citrate (pro-S)-Lyase / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000242:Cyclic AMP / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D046911:Macromolecular Substances; D008297:Male; D010446:Peptide Fragments / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014357:Trypsin
chemical_list: D000596:Amino Acids; D046911:Macromolecular Substances; D010446:Peptide Fragments; D005934:Glucagon; D000242:Cyclic AMP; D001275:ATP Citrate (pro-S)-Lyase; D011494:Protein Kinases; D014357:Trypsin