Circular dichroism (CD) is a very useful tool in peptide drug discovery.
Light absorption spectroscopy helps to determine secondary structure of polypeptide.
CD is the difference in the absorption of left-handed circularly polarized light (L-CPL) and right-handed circularly polarized light (R-CPL) and occurs when a molecule is chiral.
Example of CD spectra
The measures are taken on a range of wavelengths.
The most important applications is for study a large biological molecule.
As told before, it permits to study secondary structure or also conformation of macromolecules. Because the secondary structure is very sensitive to its environment, temperature, pH, CD is crucial.
Dichroism circular can be used to see how the secondary structure changes with the environmental conditions, interaction with other molecules.
So, obtention of thermodynamic, kinetic and structural informations can be deducted.