******************************************************************************
From: henri@icis.rmsb.u-bordeaux2.fr (Henri Valeins)
Date: 22 Oct 1996 16:22:10 GMT
Subject: Pbs differenciation Glutamic acid and Glutamine
Organization: RMSB, CNRS, Universite V. Segalen Bordeaux 2

Hello,

 What is the best technique to differenciate glutamic acid an glutamine
with Gc coupled to a mass spectrometer ?
 I tried silylation with BSA and acetonitrile or pyridine but I obtain
 essentially  pyroglutamic acid TMS ester.
   
   Thanks
    
                 ,.,
                (o o)
+-----------oOO-|(_)|-OOo------------------+-------------------------+
|Henri Valeins                             |RMSB CNRS UMR 5536       |
|Tel : 57 57 17 85                         |Universite de Bordeaux 2 |
|Fax : 56 96 13 41                         |146, rue Leo Saignat     |
|E-mail : henri.valeins@rmsb.u-bordeaux2.fr|33076 Bordeaux Cedex     |
+------------------------------------------+-------------------------+
******************************************************************************
From: Bruce Patterson <bpatters@imgate.wustl.edu>
Date: Tue, 29 Oct 1996 08:40:17 -0600
Subject: Re: Pbs differenciation Glutamic acid and Glutamine
Organization: School of Medicine -- Washington University

We have had great success with the tBDMS (tert. butyldimethylsilyl)
derivative using MTBSTFA and either acetonitrile (ACN) or
dimethylformamide (DMF) as solvent.  Glutamate does generate some
pyro-GLU.  Glutamine does not appear to give rise to glutamate.  Two
different derivatives are formed with glutamine: 3 substitutions are
preferred using ACN, whereas 4 substitutions are preferred using DMF.

Good luck!

References:

Patterson, Carraro and Wolfe, Measurement of 15N enrichment in multiple
amino acids and urea in a single analysis by gas chromatography/mass
spectrometry, Biol. Mass Spectrom. 22:518-523, 1993

Patterson, Carraro, Klein and Wolfe, Quantification of incorporation of
15N-ammonia into plasma amino acids and urea, Am. J. Physiol.
269:E508-E515, 1995

Williams and Wolfe, Determination of amino- and amide-15N glutamine
enrichment with tertiary butyldimethylsilyl derivatives.  Biol. Mass
Spectrom. 23:682-688, 1994


Bruce Patterson, Ph.D.
Washington Univ. School of Medicine, St. Louis
bpatters@imgate.wustl.edu
---------------------------------------------------------------------