Dear ABRF Members,
Has anyone out there ever coupled either chloro- or bromoacetic acetic
acid to the N-terminus of a peptide or to a MAP core using HBTU/HOBt/DIEA,
or are diimide/symmetric anhydride or diimide/HOBt the only ways of doing
this? Is chloroacetic or bromoacetic acid better for coupling to the
sulfur in cysteine? The literature seems to be divided on this. What
about the stability of N-terminal chloroacetamido vs bromoacetamido bonds?
Do any special precautions have to be taken so as not to lose the halogen
during storage? When using a MAP core, is it better to couple a short
spacer such as beta alanine first, or a long spacer such as epsilon amino
hexanoic acid? I've been thinking of preparing some chloroacetyl or
bromoacetyl MAPs to couple to peptides with N-terminal cysteine for folks
in our lab who want to raise antibodies. I like the idea of being able
to purify both the MAP core and the peptides before coupling.
I would be very grateful if members of the ABRF who have experience with
these compounds would share that expereince.
Thanks in advance for any information.
Angela C. Murphy
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Angela C. Murphy, Chemist
Lab. of Cell Biology, NHLBI, NIH
3 Center Drive, MSC 0301, Rm. B1-22
9000 Rockville Pike
Bethesda, MD 20892-0301 USA
tel.: (301) 496-2324
fax: (301) 402-1519
email: acmurphy@helix.nih.gov
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