Biophysical Assays
Biophysical Assays

Biophysical Assay Services for Drug Discovery

Biophysical assays enable understanding of the drug-target interaction on a molecular level. As a CRO we offer our clients primary and secondary biophysical screening options for the determination of the residence time, mechanism of action, and kinetics, all of which are crucial for the therapeutic action of a drug. Biophysical screening is thus essential for the selection of analytes with the most promising properties for the next stage of drug discovery.

Our team of biophysical assay experts, together with an array of cutting-edge instrumentation, is available for hit identification, hit-to-lead, and lead characterization activities tailored to the needs of your research project.

Reaction Biology offers off-the-shelf biophysical assays for high-throughput screening, custom assay development, and optimization as well as integrated projects in close interaction with our team of biophysical assay experts.

Four biophysical assays are offered at Reaction Biology CRO

Surface Plasmon Resonance (SPR) Isothermal Titration Calorimetry (ITC) Microscale Thermophoresis (MST) Thermal Shift Assay (TSA)
Physical Principle Optical measurement that detects molecular mass
changes of the target upon analyte binding
Measures the heat released or absorbed during
analyte binding to a target
Measures the changes in the motion of target molecules
along microscopic temperature gradients upon analyte
Monitors the shift in melting temperature of a target upon
analyte binding
Binding Affinity
Parameters Measured Dissociation constant (KD)
Association rate constant (kon)
Dissociation rate constant (koff)
Dissociation constant (KD)
Binding enthalpy (ΔH)
Binding stoichiometry
Dissociation constant (KD) Shift in melting temperature (ΔTm)
Capacity Medium to high throughput Low throughput Medium throughput High throughput
Sample Requirements Purified target and agents required Purified target and agents required Purified target and agents required in most cases Purified target and agents required
Dynamic Ranges pM to mM pM to mM pM to mM N/A
Advantages Provides kinetic parameters (on/off rates) and is
measured in real-time
Provides thermodynamic parameters and binding
Wide range of targets including small molecules and large
macromolecular complexes
Fast and inexpensive
Immobilization Target immobilized to the sensor chip In solution In solution In solution
Labeling Label-free Label-free Fluorescent labeling of the target required Label-free

SPR is a highly sensitive technique for accurate measurement of the interactions of two biomolecules with respect to binding kinetics and affinity as well as binding specificity.

ITC is a solution based assay that measures the heat released or absorbed as the result of a chemical reaction.

MST assays measure the motion of molecules along microscopic temperature gradients that changes upon ligand binding.

Thermal shift assays measure the thermal stability of a target protein and the increase in protein melting temperature upon the binding of a stabilizing agent. It is useful for identifying ligands, buffer conditions and cofactors affecting protein stability.