Extinction Coefficient

Extinction coefficient

Extinction coefficient

According to the ICH Q6B, one of the parameters to determine in a protein or monoclonal antibody is the extinction coefficient, also known as molar absorptivity. Extinction coefficient is a measure of how strongly a substance absorbs light at a given wavelength.

For proteins, an absorbance maximum near 280 nm(A280) in the UV spectra of a protein solution is mostly due to the presence of aromatic tryptophan, tyrosine and phenylalanine residues, and to a minor portion due to cysteine disulfide bridges.

Thus, AMSbiopharma offers a service to help you determine the extinction coefficient of your protein/mAb.

Extinction coefficient2