CHEMBL5737681

Enzyme Activity: Determination of IC50 : The Class B enzyme activities were measured in the presence of the test inhibitor in a fluorescence assay against a commercially available substrate consisting of a cephalosporin core linking 7-hydroxycoumarin to fluorescein (CCF2-FA). The enzyme (NDM-1, IMP-1 or VIM-1) and the substrate were diluted in 100 mM KH2PO4 buffer (pH 7) containing 0.005% Tween-20 and 10 μM ZnSO4. In the assay, the final concentration of enzyme was 1 pM, 2 pM and 30 pM for NDM-1, IMP-1 and VIM-1, respectively, and the final concentration of CCF2-FA was 1.25 μM. The test inhibitor was dissolved in dimethylsulfoxide and diluted 1:50 in the assay, resulting in a final concentration range of 20 μM to 0.00063 μM. In a 384-well microplate, the test inhibitor was incubated with the metallo-β-lactamase enzyme and the substrate for 2 hours at 25° C. Fluorescence at 460 nm following excitation at 405 nm was measured. The IC50 value was determined from semi-logarithmic plots of enzyme inhibition versus inhibitor concentration, with a curve generated using a 4-parameter fit.