Substrate specificity determinants for casein kinase II as deduced from studies with synthetic peptides

• Published in: The Journal of biological chemistry Vol. 262; no. 19; pp. 9136 - 9140
• Main Authors: Kuenzel, E A, Mulligan, J A, Sommercorn, J, Krebs, E G
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 05.07.1987; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Applied sciences; Biological and medical sciences; casein kinase III; Casein Kinases; Cattle; Enzymes and enzyme inhibitors; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Kinetics; Mammary Glands, Animal - enzymology; Other techniques and industries; phosphorylation; Protein Kinases - metabolism; Substrate Specificity; Transferases; Phosphorylation; Casein; Enzyme; Kinase; Substrate specificity
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)48058-1

The specificity of casein kinase II has been further defined by analyzing the kinetics of phosphorylation reactions using a number of different synthetic peptides as substrates. The best peptide substrates are those in which multiple acidic amino acids are present on both sides of the phosphorylatable serine or threonine. Acidic residues on the NH2-terminal side of the serine (threonine) greatly enhance the kinetic constants but are not absolutely required. Acidic residues on the COOH-terminal side of the serine (threonine) are absolutely required. One position for which the occupation of an acidic residue is especially critical is the position located 3 residues to the COOH terminus of the phosphate acceptor site, although the presence of an acidic amino acid in the positions that are 4 or 5 residues removed may also provide an appropriate structure that will serve as a substrate for the kinase. Aspartate serves as a better amino acid determinant than glutamate. A relatively short sequence of amino acids surrounding the phosphate acceptor site appears to serve as the basis for the specificity of casein kinase II. The peptides in this study were also assayed with casein kinase I and the casein kinase from the mammary gland so that the specificities of these kinases could be compared to that of casein kinase II.