Hsp90β (heat shock protein 90) is a molecular chaperone with essential functions in maintaining transformation. Inhibition of Hsp90β function has been shown to play a role in tumorigenesis and disease progression. The Hsp90β Assay Kit is designed for the identification of Hsp90β inhibitors using fluorescence polarization. The assay is based on the competition of fluorescently labeled geldanamycin, an HSP90 inhibitor, for binding to purified recombinant Hsp90β.

The key to the Hsp90β Assay Kit is the fluorescently labeled geldanamycin. Only one simple step on a microtiter plate is required for Hsp90β reactions. The FITC-labeled geldanamycin is incubated with a sample containing Hsp90β enzyme to produce a change in fluorescent polarization. The FP signal is measured using a fluorescent microplate reader capable of measuring fluorescence polarization.