A novel synthetic substrate for casein kinase 2.
The nonapeptide DTDSEEEIR, corresponding to amino acid residues 78-86 of calmodulin, was synthesized, and its kinetics of phosphorylation by casein kinase 2 was examined. In the presence of 4 microM polylysine, the phosphorylation rate by casein kinase 2 was 16 times greater than that of synthetic substrate peptide RRREEETEEE reported previously, and almost 1 mol of 32p was incorporated per mol of nonapeptide in 60 min at 37 degrees C. The peptide was not phosphorylated by any other protein kinase. The Thr residue was phosphorylated by casein kinase 2, but Ser was not. The Km value of casein kinase 2 for the nonapeptide was 60 microM, comparable to that of casein, and Vmax for the nonapeptide was 4 times greater than that for casein. Addition of polylysine did not affect the Km value but markedly increased Vmax.
Hagiwara
T
T
School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
Nakaya
K
K
Nakamura
Y
Y
D000595:Amino Acid Sequence; D002147:Calmodulin / Q000378:metabolism*; D047388:Casein Kinases; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism*; D010766:Phosphorylation; D011107:Polylysine / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D013379:Substrate Specificity
D002147:Calmodulin; D009842:Oligopeptides; D010446:Peptide Fragments; D011107:Polylysine; D011494:Protein Kinases; D047388:Casein Kinases