John,
I read with interest your capping procedure. I use a pioneer peptide
synthesiser which P.E Biosystems recommends you do not use DCM. Do you think
DMF would also work (with the benzoic anhydride)?
Neil. Brew
-----Original Message-----
From: John S. McMurray, Ph.D. [mailto:jsmcmur@audumla.mdacc.tmc.edu]
Sent: 27 April 2000 16:37
To: Recipients of ABRF List
Subject: Re: Pepsyn: capping strategies
Joseph,
The core lab here at MDACC caps with benzoic anhydride when using either
Boc- or Fmoc-based solid phase peptide synthesis. This procedure adds more
hydrophobicity thus increasing retention time on RP-HPLC. In addition the
absorbance at 254 nm is about 10x that of Phe, so capped sequences are
readily detected, especially with a doide array detector.
The procedure was worked out by Ron Shonk here and was described in a
poster at one of the American Peptide Symposia several years ago (I do not
believe that it went into the procedings and I can not remember wigh
symposium).
Basically the reagent is 10% benzoic anhydride and 2.5%
diisopropylethylamine in dichloromethane. Our group lets it react for an
hour but shorter times may work just as well.
Good luck.
John
John S. McMurray
The University of Texas M. D. Anderson Cancer Center
Department of Neuro-Oncology, Box 316
1515 Holcombe Blvd.
Houston, TX 77030
Ph: 713-745-3763
Fax: 713-745-1183
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