title: An assay for acidic peptide substrates of protein kinases.
abstract: The assay of acidic peptides as substrates for protein kinases has not been as easy to perform as testing basic peptides or polypeptides. We have developed a simple, rapid, and cost-effective procedure that allows the design and testing of potential peptide substrates without the constraints imposed by the phosphocellulose filter paper method (the need to incorporate positively charged residues into the peptide sequence). The technique combines the chelation of 32Pi by acid molybdate with PEI-cellulose chromatography. In this way the migration of 32P-labeled Pi, ATP, and protein are impeded while phosphopeptide is eluted in 1.5 ml from a 0.25-ml disposable column. In order to validate the assay we used two angiotensin II analogues as peptide substrates for the protein tyrosine kinase pp60c-src. The assay results using the new procedure were compared to those of the phosphocellulose filter paper technique. We also demonstrated the use of this method to test linear and cyclic peptides that could not be assayed with the phosphocellulose paper technique. This assay will aid those who are attempting to determine the substrate specificity of protein kinases.
authors.affiliation: Department of Neuro-Oncology, University of Texas M. D. Anderson Cancer Center, Houston 77030.
authors.forename: R J
authors.initials: RJ
authors.lastname: Budde
authors.forename: J S
authors.initials: JS
authors.lastname: McMurray
authors.forename: D A
authors.initials: DA
authors.lastname: Tinker
mesh_terms: D000255:Adenosine Triphosphate / Q000302:isolation & purification / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography / Q000379:methods; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002852:Chromatography, Ion Exchange / Q000379:methods; D002855:Chromatography, Thin Layer / Q000379:methods; D007313:Insecta; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000302:isolation & purification / Q000378:metabolism; D010748:Phosphopeptides / Q000138:chemical synthesis; D010761:Phosphorus Radioisotopes; D011494:Protein Kinases / Q000032:analysis / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D010455:Peptides; D010748:Phosphopeptides; D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)