>To complement the MALDI-TOF, we would like a good instrument for
>fragmentation and other analyses that are not easily done on the MALDI.
>These are the names of instruments we are interested in:
>
>QTOF - QSTAR - LCQdeca - Esquire
>******************************************************
>Ulf Hellman, Ph. D.
Dear Ulf,
I think your choice of instruments depends on your needs as well as your
budget. If you only need to generate sequence tags to identify proteins
whose sequences can be found in public databases then perhaps one of the
more economical instruments will do. But if you need to generate de novo
sequences of peptides from unknown proteins then I think the Q instruments
become very useful. Of the mass specs you mention, I have experience only
with the Micromass Q-TOF during the past half year or so. It has proven to
be robust and reliable, and, for an ms/ms machine, easy to use. The
software is very good, as has been customer support. We have found that it
is very easy to read correct sequences of 5-15 or sometimes more amino
acids from doubly and sometimes triply charged precursor ions from in-gel
tryptic digests. This means we can tell Q from K but of course not I from
L. If the sequence or sequence tag doesn't identify a protein from the
databases sometimes we can identify a related protein from another species
using a BLAST homology search, or use the sequence info for cloning. In
these cases especially I think the high accuracy of the Q-TOF comes in
handy. I hope this helps.
Tom Neubert
_______________________________________________
Thomas A. Neubert, Ph.D.
Skirball Institute of Biomolecular Medicine
New York University School of Medicine
540 First Avenue, Lab 5-18
New York, NY 10016
office telephone: (212) 263-7265
lab telephone: (212) 263-7266
fax: (212) 263-8214
e-mail: neubert@saturn.med.nyu.edu