From: RH01358@rh.dk
Message-Id: <9701171505.AA13999@rhden1.rh.dk>
Date: Fri, 17 Jan 1997 15:57:00 NFT
Subject: lost protein, MALDI-MS
To: Recipients of ABRF List <abrf@aecom.yu.edu>
A few days ago Rick Edmondson noted a problem with no signal from a
specific protein.
As you have probably also have noted, proteins (and peptides) give
very variable signals, depending on structure. Some times we see no
signal even with several pmols loaded, and this is not due to sticking
to tube walls, since the same solution can give beautiful signal in
the sequencer.
Recently, however, we got very good signal from some (different)
proteins using alfa-cyano-4-hydroxycinnamic acid (usually recommended
for peptides) while no signal was seen with sinnapinic acid. In one
case inclusion of 20mM n-octylglucosid as well did the trick, but in
other cases signal is not influenced very much.
You could also check Cohen & Chait: Influence of matrix solution
conditions..., Anal.Chem. 68:31-37 (1996)
good luck
Anders H. Johnsen
Department of Clinical Biochemistry
University of Copenhagen
KB3014, Rigshospitalet
Blegdamsvej 9
DK-2100 Copenhagen, DENMARK
phone: (+45) 3545 3007
fax: (+45) 3545 4640
e-mail: johnsen@rh.dk