title: Cardiac troponin I, isolated from bovine heart, contains two adjacent phosphoserines. A first example of phosphoserine determination by derivatization to S-ethylcysteine.
abstract: Bovine cardiac troponin containing approximately 3 mol P/mol protein could be separated into its subunits without loss of phosphate. Troponin I and troponin T each contain about 1.5 mol P/mol protein. In troponin I two phosphorylated serine residues could be localized in the N-terminal region by conversion of phosphoserine to S-ethylcysteine. They are located in adjacent positions in the following sequence: -Arg-Arg-Ser(P)-Ser(P)-Ala-Asn-Tyr-Tyr-Arg-Ala-Tyr-Ala-Thr-Glu-Pro- His-Ala-Lys. This sequence shows that the first phosphoserine residue in bovine cardiac troponin I occupies a homologous position to phosphoserine-20 of rabbit cardiac troponin I.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism; D008666:Metalloendopeptidases; D008969:Molecular Sequence Data; D009206:Myocardium / Q000032:analysis*; D010446:Peptide Fragments / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis* / Q000378:metabolism; D012694:Serine / Q000031:analogs & derivatives*; D014336:Troponin / Q000032:analysis*; D014357:Trypsin / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D010710:Phosphates; D014336:Troponin; D010768:Phosphoserine; D012694:Serine; C026826:S-ethylcysteine; D010450:Endopeptidases; D014357:Trypsin; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; D003545:Cysteine