Molar extinction coefficient of a protein

Alan Cooper alanc at
Fri Mar 17 08:48:12 EST 1995

In article ngb at, madi at (Marc DIEU) writes:
> Is it possible to determine the molar extinction coefficient at 280 nm
> of a given protein (epsilon 280 nm prot.) simply by additionning the
> individual molar extinction coefficients of the different aromatic
> residues which compose the sequence of the protein ? Is it correct or
> not ? Is there any literature available about it ? Is the absorbance of
> a residue influenced by its environment or by its position in the
> three-dimentional structure of the protein ? The non-aromatic residues,
> do they also contribute to some extent to the absorbance of the protein
> at 280 nm ? What is the value of the molar extinction coefficient at
> 280 nm of Trp, Tyr, Phe and His ? 
> Dominique DELFORGE,
> Laboratory of Cellular Biochemistry,
> FacultŽs Universitaires ND de la Paix,
> 61, rue de Bruxelles,
> B-5000 Namur (Belgium).
> Fax: ++/32/81/72.41.35.
> Email: dodel at

Try:	Gill & von Hippel (1989)	Anal.Biochem. 182, 319-326
	"Calculation of protein extinction coefficients from amino acid sequence data"

	- usually good to +/- 5%

More information about the Methods mailing list