A Synthetic Peptide Substrate Specific for Casein Kinase II

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 82; no. 3; pp. 737 - 741
• Main Authors: Kuenzel, Elizabeth A., Krebs, Edwin G.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.02.1985; National Acad Sciences
• Subjects: Amino acids; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Biotechnology; casein kinase II; Casein Kinases; Cattle; Cyclic AMP - metabolism; Cyclic GMP - metabolism; Enzyme engineering; Enzyme substrates; Enzymes; Enzymes and enzyme inhibitors; Epidermal Growth Factor - metabolism; Fundamental and applied biological sciences. Psychology; Heparin; Heparin - pharmacology; Humans; Improved methods for extraction and purification of enzymes; Insulin - metabolism; Kinetics; Liver; Methods. Procedures. Technologies; Oligopeptides - chemical synthesis; Oligopeptides - metabolism; peptides; Phosphates; Phosphorylation; Protein Kinases - metabolism; Rabbits; Resins; Substrate Specificity; Transferases; Ungulates; Specific activity; Measurement; Purification; Synthetic substrate; Peptides; Protein kinase; Substrate specificity; Kinetics; Method; Catalyst activity
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.82.3.737

A synthetic peptide having the sequence Arg-Arg-Arg-Glu-Glu-Glu-Thr-Glu-Glu-Glu was found to serve as a convenient substrate for the protein kinase generally referred to as casein kinase II. The enzyme exhibited an apparent Kmof 500 μ M for the peptide, as compared to an apparent Kmof 50 μ M for casein. The maximum velocities for phosphorylation of the peptide and of casein were similar. The peptide was not phosphorylated by any of eight other protein kinases, all of which were shown to be active toward their known substrates. The peptide was used to monitor activity during steps in the purification of casein kinase II from bovine liver. These experiments demonstrated that with this peptide it is now possible to obtain specific measurements of casein kinase II activity in crude enzyme preparations.