From: Borries Demeler <demeler@selway.umt.edu>
  To  : demeler@selway.umt.edu
  Date: Thu, 29 Jun 1995 13:47:35 -0600

Re: Extinction Coefficient (fwd)

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From: Reggie Aurora <reggie>
Newsgroups: bionet.software
Subject: Re: Extinction Coefficient
Date: 28 Jun 1995 21:45:18 GMT
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marian@micro.ifas.ufl.edu (Marian Buszko) wrote:
>Is there a software program available to calculate the extinction coefficient
>of a protein at 280 nm if the complete sequence of the protein is known?
>If so, I would be interested in obtaining this program.
>
>Thank you, 
>
>Julie Maupin-Furlow
>M. Buszko (marian@micro.ifas.ufl.edu)
>University of Florida, Microbiology  
>

I don't have a program but it's so easy that you may not need one.
Check the following ref: Gill and von Hippel Anal Biochm 182:319-326 (1989)
Basically, count the number of Tyr multiply by 1280 add # of Trp times 5690
and add # of Cys times 120 = Extincion coeff at 280 in per Molar per cm.
Usually accurate to within 5%.  If you want to do the control measure the
absorption at 280 in buffer and in buffer+ 6M urea.  The ratio of the two
will be the correction factor for environment. 

---------------- **** ----------------   
	Reggie Aurora 
	Dept of Biophysics WBSB 701
	Johns Hopkins Scool of Medicine 
	725 N. Wolfe St.
	Baltimore, MD 21205
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