What is DSC?
Differential Scanning Calorimetry or DSC measures the heat change
during thermal denaturation of biomolecule samples.
Particularly engineered proteins and biopharmaceutical products.
DSC is universally considered the gold standard for measuring TM
or the melting temperature of proteins in solution.
DSC presents the TM as the peak of the data plot.
Importantly DSC is the only known, reliable method
to directly measure unfolding thermodynamics of protein samples.
From a native, active conformation
to a denatured, inactive conformation.
DSC thermal stability assays provide details on how the protein unfolds,
enabling protein engineers to identify stable constructs,
as well as optimizing purification strategies and storage conditions.
The main parameter measured by thermalstability assays is the Thermal Transition Temperature or TM.
The TM is the temperature at which 50% of the protein is native and 50% is denatured.
It's the most reliable indicator of thermal stability.
The higher the TM the more stable the protein is
which is why TM screening is universally used to select the most stable engineered protein,
as well as the buffers and additives which can further stabilize it.
How does DSC work?
During a DSC experiment the protein in the desired buffer is placed in the sample cell.
A matched buffer is placed in the reference cell.
At the starting temperature the protein still retains its native shape and structure
as the sample and reference cells heat up, the protein begins to thermally denature.
The proteins heat capacity CP increases as the protein unfolds.
The TM is shown at the peak of the resulting data plot.
At the end of the experiment all of the protein is unfolded.
Data Interpretation
The area under the peak is the total energy change,.
Enthalpy, that corresponds to the protein unfolding.
This is an endothermic reaction.
Since energy is required to break the non covalent bonds
which maintain the protein in its higher order structure
Thermal stability data from DSC is an essential tool
in the biophysical characterization of proteins and biopharmaceuticals
during protein engineering, formulation development and bio comparability studies.
Since DSC is the gold standard TM assay,
the technique is an essential stability screen in biopharmaceutical discovery and development.
Reliability of Technique
DSC is label-free using only native molecules.
This eliminates the need for added dyes or chemical modifications
producing more reliable results than traditional fluorescence assays
which frequently introduce unwanted artifacts.
How DSC Adds Value
You can use DSC to quickly and accurately rank order the TM of the same protein
in different formulation buffers
The formulations with the highest TM can be selected for further study.
By using the thermodynamic profiles created by DSC
you can quickly and accurately compare engineered proteins and biopharmaceutical products
from different batches and different manufacturing sites,
ensuring consistent quality throughout the production chain
Using DSC Equipment
Malvern's' MicroCal PEAQ-DSC systems
use small sample volumes,
are easy to operate,
can also be automated for a high throughput
with solutions available for 21 CFR part 11 compliance
MicroCal DSC data is the trusted gold standard.
For more information on MicroCal DSC and how it can support your research,
please visit: www.malvernpanalytical.com/MicroCal
or contact your regional Malvern Panalytical sales office.