Date: Thu, 16 Jan 1997 12:14:58 -0600
Message-Id: <v0153050daf051e42450e@[128.252.197.88]>
To: abrfhyp@cco.caltech.edu
From: rskubish@pharmdec.wustl.edu (Richard Skubish)
Subject: Peptide with many Arg's
>Mime-Version: 1.0
>Date: Tue, 2 Jul 1996 12:50:14 -0600
>Old-To: abrf@aecom.yu.edu
>From: jgorka (John Gorka)
>Subject: Re: Peptide with many Arg's
>To: Recipients of ABRF List <abrf@aecom.yu.edu>
>Sender: Association of Biomolecular Resource Facilities
><abrf-request@aecom.yu.edu>
>Precedence: bulk
>
>>I need to synthesize a 27-mer peptide that has 9 Arg residues. Does anyone
>>have any suggesstions on how to improve my chances for success. The rest of
>>the peptide is largely Glu, Lys, and Leu.
>>
>>I will be using FMOC chemistry and TFA cleavage/deprotection. I plan to
>>extend the cleavage time to around 4 hr and use the standard King mixture
>>of TFA/phenol/ethanedithiol/thioanisole/water.
>>
>>TIA,
>>Jeff Mathers
>>Peptide Synthesis Manager
>>The Protein/DNA Technology Center
>>The Rockefeller University
>>http://pdtc.rockefeller.edu
>
>
> Jeff,
> Given that the remaining residues in the peptide are Lys,Glu,& Leu, I
>would send this peptide out and have a 2 hr. HF cleavage done on it. Anita
>Hong at ANASPEC would be a very good person to have do this and I'm pretty
>sure she offers this service for a fee.I personally have done HF cleavages
>on Fmoc peptides containing as many as 8 Arg(pmc) residues.The other
>option, which I haven't tried is to synthesize the peptide using Fmoc
>Arg(pbf) and do a 2-4 hr
>TFA cleavage using reagent K if you desire, but with the limited additional
>protecting groups (Boc&OtBu) you could get by with a less complex cleavage
>cocktail. The rule of thumb I use is any peptde with >5 Arg(pmc) residues
>automayically gets HF cleaved.The only problem with this approach is that
>sometimes for some reason trityl groups may not be easily removed during
>the HF process( I believe that this has something to do with the anhydrous
>conditions of the HF cleavage).If trityls are present,as indicated by mass
>spectrometry, then a simple solution phase TFA cleavage of the cleaved
>peptide can be performed to remove the remaining trityl groups.They are
>readily removed in as low as 25% TFA(personal observation).
>
> Good Luck!
> Sincerely,
>
> John Gorka
>jgorka@pharmdec.wustl.edu
>1-314-362-0282
>
Richard Skubish
rskubish@pharmdec.wustl.edu
314-362-0283
Washington University Medical School
Box 8103 - PNACL
660 S. Euclid
St. Louis, MO 63110