| abstract |
Isolated peptide substrates of Plk1 and nucleic acids encoding these peptides are disclosed. The peptides include two to ten repeats of the amino acid sequence set forth as X 1 X 2 AX 3 X 4 X 5 PLHSTX 6 X 7 X 8 X 9 X 10 X 11 X 12 (SEQ ID NO: 1), in which within each repeat X 1 , X 2 , X 6 , X 7 , X 8 , X 9 , X 10 , X 11 , and X 12 are each independently any amino acid or no amino acid, and X 3 and X 4 are each independently any amino acid. Methods of using these peptides to detect Plk1 activity in a sample are also disclosed. In some examples, the method includes contacting a sample with a disclosed peptide substrate of Plk1 in the presence of adenosine triphosphate, or an analog thereof, for a period of time sufficient for Plk1 to phosphorylate the PBIPtide. The presence and/or amount of the phosphorylated and/or the unphosphorylated peptide is detected, thereby detecting and/or quantitating Plk1 kinase activity in the sample. |