Inhibition of Trypanosoma brucei N-myristoyltransferase assessed as transfer of [3H]-myristic acid to a biotinylated substrate peptide (GCGGSKVKPQPPQAK(biotin)-amide by scintillation proximity assay
Inhibition of human N-myristoyltransferase 1 assessed as transfer of [3H]-myristic acid to a biotinylated substrate peptide (GCGGSKVKPQPPQAK(biotin)-amide by scintillation proximity assay
Antitrypanosomal activity against Trypanosoma brucei BSF427 expressing VSG118 infected in human MRC5 cells assessed as reduction cell viability incubated for 69 hrs by rezasurin dye based assay
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.
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.
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.