title: Characterization of the platelet-derived growth factor beta-receptor kinase activity by use of synthetic peptides.
abstract: Synthetic peptides derived from the sequence surrounding tyrosine-857 in the human platelet-derived growth factor (PDGF) beta-receptor were used to elucidate the requirement for length and presence of negative and positively charged amino acids in substrates of the PDGF beta-receptor protein tyrosine kinase. The measured Km for the different peptides were all in the range 1-10 mM. A peptide of only five amino acids, lacking acidic amino acid residues, were found to be substrates for the receptor kinase. Ligand binding was found to stimulate the phosphorylation of peptides mainly by lowering the Km both for peptide and for ATP. Only minor changes in the Vmax occurred upon stimulation with PDGF. The reaction mechanism was found to be sequential, i.e. both the peptide and ATP have to bind to the enzyme before any product is released.
authors.affiliation: Ludwig Institute for Cancer Research, Biomedicum, Uppsala, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Rönnstrand
authors.forename: A
authors.initials: A
authors.lastname: Sorokin
authors.forename: U
authors.initials: U
authors.lastname: Engström
authors.forename: C H
authors.initials: CH
authors.lastname: Heldin
mesh_terms: D000595:Amino Acid Sequence; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D009842:Oligopeptides; D010982:Platelet-Derived Growth Factor; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D011494:Protein Kinases; D017479:Receptors, Platelet-Derived Growth Factor