Date: Tue, 21 Jan 1997 08:06:57 -0800
Message-Id: <2e4ea710@ccgate.berlex.com>
From: Joe_Traina@berlex.com (Joe Traina)
Subject: Re: No mass data by MALDI-TOF
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Jeff,
You might find some help in the following reference:
Moniatte, M. et al.; FEBS Letters 384 (1996) 269-272.
They discuss the MALDI-TOF MS analysis of a non-covalently bound
heptamer (MW 332 kDa.). The +1 through +4 charge states of the
heptamer were observed as well as the M+, M2+ and M3+. They state
that the spectra could only be observed within a narrow concentration
window of 1.5-0.5 pmol/uL (analyte/matrix ratio 1/20000 - 1/50000).
Sinapinic acid (13 mg/mL) in H2O, 0.1% TFA/CH3CN (1:1) was the
matrix.
I hope this helps,
Joe Traina, Berlex Biosciences, Richmond CA (joe-traina@berlex.com)
______________________________ Reply Separator _________________________________
Subject: No mass data by MALDI-TOF
Author: JCaplan339@aol.com at Internet
Date: 1/20/97 7:20 PM
Hi,
I have a couple of questions regarding MALDI-TOF. We are using a Finnigan
LASERMAT 2000 mass spec. and were recently asked to mass a protein with an
approx. mol. mass of 90 kDa. Using other analytical techniques, the protein
appears to form multimers (not quite sure of the mechanism) - potentially
quite large. Our thought was that the monomer form should be able to be
seen. The matrix used was Sinapinic Acid and the protein was in water. We
could not see anything with an approximate 10pmol spot. Other amounts were
used and still nothing could be seen. Does anyone have any suggestions?
Should I try a different matrix (ACH)?. How large of a protein can one
typically see using MALDI-TOF?
Does anyone use a LASERMAT 2000? If so, how do you like it and what type of
error% do you typically see.
Thank you very much,
Jeff (Jeffrey Caplan)
The accompanying eMail address is my home eMail address. My work eMail
address is Jeffrey_Caplan@Internetmail.PR.Cyanamid.com.