The assay aimed to find inhibitors that target Plk1 polo-box domain (PBD) using a fluorescence polarization (FP) assay. Plk1 is a crucial protein kinase in cell proliferation and plays a major role in cancer cell viability. The assay used a FITC-conjugated phospho-9-mer (p-9-mer) peptide and purified human Plk1 PBD protein. The identification of small molecule inhibitors of Plk1 PBD could be developed into useful tools for biomedical and clinical research for anti-cancer therapy. Is the molecule effective to this assay?