[Protein-analysis] Re: Extinction coefficient

Geoff Briggs geoff.briggs at nottingham.ac.uk
Tue Jun 27 03:19:33 EST 2006

Anshul wrote:
> Hi all,
> I am working with papain and wanted to know about its extinction 
> coefficient at 280 nm. I searched the internet and found it to be 25 but 
> when I checked through the ProtParam tool of expassy it showed me the 
> value as 56185.
> Does anyone know what the exact value of extinction coefficient is for 
> papain.
> Regards,
> Ansh

I used to work with papain, and the value of 25 is correct. However, as 
DK says, this is for a 10mg/ml solution, rather than the more normal 
1mg/ml solution. A check of my thesis reminds me that this was 
determined experimentally by Glaser & Smith in 1961 (J Biol Chem 


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