Receptor Binding Assays

MultiScreen_HTS 96- and 384-well filter plates for separating free from bound, labeled ligand

Receptor-binding assays are a critical component in lead indentification and later lead characterization processes. They are used to characterize most known drug targets and typically use
filter-based separations technology to obtain necessary “bound vs. free” fractions for assay validation. For sensitivity and specificity, radiolabeled known drugs are used in competitive binding assays. The assay is designed as a competitive inhibition assay using the radiolabeled known drug/ligand receptor interaction to screen chemical or natural product libraries for more effective NCEs (new chemical entities).

These quantitative binding parameter determinations indicate the minimal effective drug concentrations. MultiScreen_HTS plates for quantitative binding parameters provide a more accurate and reliable alternative to homogeneous assays. They are widely used in high throughput screening campaigns and provide a reliable platform that incorporates a range of glass fiber filters to retain the receptor and “bound” ligand fraction. Operation by vacuum manifold allows for more convenient characterizations since the bound fractions are easily collected from the top of the plate.

The improved plate design of MultiScreen_HTS automation-compatible
filter plates facilitates use with gripper arms and is compatible with microplate scintillation counters.

MultiScreen_HTS+ Hi Flow filter plates: improve washing efficiency and reduce data variation.

MultiScreen Harvest plates are also available to withstand the numerous washes and batch pretreatment (PEI) required in cell harvest protocols.

Highly sensitive and specific radiometric assays

   • Compatible with liquid scintillation cocktail
   • Improved automation compatibility with new MultiScreen_HTS filter plates

Protocol

Performance

Optimized Design for High Quality Results

384-well Displacement Binding of Human Muscarinic M1 Receptor

96-well Displacement Binding of Human Muscarinic M1 Receptor

Radioligand binding displacement binding assays were performed with a constant radiolabeled scopolamine concentration (0.6 nM) and serial dilutions of unlabelled pirenzipine as compared to a control binding experiment without unlabelled pirenzipine (% of Control). Left: Displacement binding done with 4.38 µg receptor preparation in 100 µL using MutliScreen_HTS 384-well filter plate. Results presented are from three separate experiments each performed in triplicate wells. Right: Displacement binding done with 8.75 µg receptor preparation in 200 µL using MutliScreen 96-well filter plate. Relative affinity values (IC50) were determined by fitting displacement binding inhibition values by non-linear regression using Prism™ data software. All data points are the average of triplicate experiments. Filter plates were dried prior to the addition of Supermix™ (10 µL in 384-well plates and 50 µL in 96-well plates). Counting was done in a MicroBeta® Trilux. NOTE: All counting is done with underdrain on for both 96- and 384-well plates.