Assay Report Card

ID: ALA3887335

Type: Binding

Description: Enzyme Inhibition Assay: Measurements were performed using a modification of the scintillation proximity assay platform described previously by Georgopapadakou, N. H. et al. (22nd International Congress on Chemotherapy, 2001, Abstract P16.001). Compounds were solubilised in DMSO at a top concentration of 10 mM and serially diluted in half log steps to achieve a range of final assay concentrations of 100 uM to 1 nM. Compound at each concentration (100-fold final) was added to white 384 well plates in a volume of 0.5 ml. Human, A. fumigatus, T. brucei or L. major N-myristoyl transferase enzyme, dissolved to a working concentration of 10 nM in assay buffer (30 mM Tris/HCl pH 7.4, 0.5 mM EGTA, 0.5 mM EDTA, 1.25 mM DTT, 0.1% Triton X-100), was then added to columns 1 to 11 and 13 to 23 of the plates in a volume of 20 ml. To columns 12 and 24, 20 ml assay buffer was added to provide a no enzyme control. Following a 5 minute incubation at room temperature the substrates (GCGGSKVKPQPPQAK(Biotin)-Amide and myristoyl coenzyme A), dissolved in assay buffer, were added to all wells in a volume of 20 ml to start the reaction. The final concentrations of peptide and 3H-myristoyl coenzyme A were 0.5 mM and 125 nM respectively and the specific activity of the radiolabel was 8 Ci/mmol. Plates were then incubated at room temperature for up to 50 minutes (dependant upon the period of linearity for the different enzyme species) before SPA beads, suspended to 1 mg/ml in a stop solution (200 mM Phosphoric Acid/NaOH pH 4, 750 mM MgCl2), were added in a volume of 40 ml.