Date: Thu, 16 Jan 1997 12:19:12 -0600
Message-Id: <v01530516af051f3d801f@[128.252.197.88]>
To: abrfhyp@cco.caltech.edu
From: rskubish@pharmdec.wustl.edu (Richard Skubish)
Subject: peptide synthesis -18 mass
>Mime-Version: 1.0
>Date: Mon, 26 Aug 1996 07:07:37 -0700
>From: Nick_Ede@cc.chiron.com (Nick Ede)
>Subject: Re: peptide synthesis -18 mass
>Old-To: RIFLEMAN@uthscsa.edu, abrf@aecom.yu.edu
>To: Recipients of ABRF List <abrf@aecom.yu.edu>
>Sender: Association of Biomolecular Resource Facilities
><abrf-request@aecom.yu.edu>
>Precedence: bulk
>
> Peggy,
>
> One easy way to confirm the presence of aspartimide is to treat the
> mixture with alittle 0.1M NaOH, wait 10-15 min and then inject onto
> HPLC. If aspartimide is present, it will hydrolyse back to a mixture
> of both the alpha and beta linked peptides. The imide form usually is
> the later eluting peak on HPLC.
>
> Nick Ede
> Chiron Mimotopes
>
>
>______________________________ Reply Separator
>_________________________________
>Subject: peptide synthesis -18 mass
>Author: RIFLEMAN@uthscsa.edu at SMTP
>Date: 8/23/96 1:59 PM
>
>
>A problem for the weekend:
>
>We have synthesized a peptide which comes out to be 2 major peaks: The
>correct
>Mass and the -18 mass.
>
>The peptide does have an asp-gly which could go to succinimide, and then back
>to asp and isoasp.
>
>It also has several sers that can go to dehydroalanine and several tyrosines.
>Is it possible for tyrosine to go to dehydrophenylalanine? How common is it
>to get any one of these alternatives, and is there another alternative for -18
>mass?
>
>The -l0 peak seems to be pretty stable. Does anyone know how stable the above
>3 alternatives are? In other words, could we count on the concentration to be
>stable in an assay? On the sequencer?
>
>Peggy Rifleman
>University of Texas Health Science Center
>San Antonio, Texas
>e-mail: Rifleman@uthscsa.edu
>Home Page: HTTP://bioc02.uthscsa.edu/~rifle_p/new.html
>
>
Richard Skubish
rskubish@pharmdec.wustl.edu
314-362-0283
Washington University Medical School
Box 8103 - PNACL
660 S. Euclid
St. Louis, MO 63110