Ordered phosphorylation of a duplicated minimal recognition motif for cAMP-dependent protein kinase present in cardiac troponin I.
Cardiac troponin I contains two adjacent serines in sequence after three arginine residues thus making up a minimally duplicated recognition motif for cAMP-dependent protein kinase. In a synthetic peptide, PVRRRSSANY, the two serine residues are phosphorylated sequentially with the intermediate formation of a monophosphorylated species according to the following reaction sequence: Peptide k1----Peptide-P k2----Peptide-P2. The calculated rat constants are: k1 = 0.435.min-1 and k2 = 0.034.min-1. Sequence analyses of the monophosphopeptide and its tryptic fragments show that the predominant monophosphoform carries phosphate at the second serine.
Mittmann
K
K
Ruhr-Universität Bochum, Abteilung für Biochemie Supramolekularer Systeme, Germany.
Jaquet
K
K
Heilmeyer
L M
LM
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D000242:Cyclic AMP / Q000494:pharmacology*; D007700:Kinetics; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry*; D010446:Peptide Fragments / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D014336:Troponin / Q000737:chemistry / Q000378:metabolism*; D019210:Troponin I; D014357:Trypsin / Q000378:metabolism
D000596:Amino Acids; D010446:Peptide Fragments; D014336:Troponin; D019210:Troponin I; D000242:Cyclic AMP; D011494:Protein Kinases; D014357:Trypsin