No. Even at the wavelength where the amide bond absorbs (214 and 280 nm) you must have a ‘pure’ solution of the protein and know the number of amide bonds (amino acids in the protein). Thus, the requirement for the ‘pre’ standard.

But all proteins have the same extinction coefficient since they have the same 20 L-amino acids. It’s around 185-195 nm (around water). What is the purpose of obtaining the extinction coefficient?

Hi Samaria,

You question is not clear to me.Do you want to calculate extinction coefficient, if yes , you can , as you has a sample and you know the concentration and the sample has absorbance at specific wavelength use Beers law,

A = εbc

where A is absorbance (no units) ε is the molar absorptivity with units of L mol-1 cm-1 (formerly called the extinction coefficient) b is the path length of the sample, usually expressed in cm c is the concentration of the compound in solution, expressed in mol L-1

Good Luck

What do you need the extinction coefficient for?

I want to measure the dye: protein ratio. For that the equations require the extinction coefficient of the protein which I dont have.

Hello, may I ask if u were able to find a reference for the extinction coefficient of gliadin? I would also like to calibrate the concentration of my gliadin ethanol extracts from Sigma Aldrich crude gliadin product in my spectrophotometric determination at 280 nm . Thank you