The amount of the given protein is determined using Beer-Lambert law (equation 4.3):

 

Notes:

1.  If the given protein lacks Trp, Tyr, and disulfide linkages, the concentration can be estimated using A ₂₀₅ or A ₂₁₅ and A ₂₂₅ using equations 4.6 and 4.7.

2.  If the protein solution is turbid, it will scatter light leading to inflated absorbance values. The solution should therefore be cleared either by filtering it through a 0.2 μm filter or through centrifugation.

References:

1.  Scopes, R. K. (1974) Measurement of protein by spectrometry at 205 nm. Analytical Biochemistry, 59, 277–282.

2.  Waddell, W. J. (1956) A simple UV spectrophotometric method for the determination of protein. The Journal of Laboratory and Clinical Medicine, 48, 311–314.