>I have an additional question on the alkylation--if you can get
alkylation
>of the epsilon amino group of lysine, can you get alkylation of the
>n-terminal amino group of proteins/peptides?
>Deb,
I recall a monograph published by Applied Biosystems in which David
Hawke was either the author or one of the authors (may be no. 28,
1987?) which attempted to derivatize proteins with 4vp directly on the
polybrene filter prior to sequencing. The bottom line was that they saw
considerable "previewing". This was presumably due to the reaction of
the reagent with the N-terminal residue and subsequent cyclization and
cleavage with TFA. I have also seen this. Therefore, it is important to
minimize this reaction. I think if one keeps the pH below 8 (amino
groups mostly protonated) and the reagent at reasonable levels (does
anyone know why historically procedures suggest tossing in
<underline>neat</underline> 4vp?) you you may be able to avoid N-
reactivity. Sorry I don't have an exact reference to Dave's procedure,
but hope this helps anyway.
regards
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Gary M. Hathaway, Director
PPMAL - Protein/Peptide Micro Analytical Laboratory
California Institute of Technology
139-74, Division of Biology
Pasadena, CA 91125
http://www.cco.caltech.edu/~ppmal
email Gary: hathaway@caltech.edu
email facility: ppmal@caltech.edu
phone: lab (818) 395-6388 or office (818) 395-2769
FAX (818) 449-3414
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