Thomas,
Capping can be useful, but, I'd not do it at every
step at it can be a waste of time and reagents. There
are areas in your sequence that it would be more
useful than others. For example, after each coupling
of Isoleucine I would cap because it is a difficult
coupling at best for adding Ile to most anything.
Since the acetylated truncations would be fairly well
removed form the N-terminus they should resolve ok
from the target, if they exist at all. I have coupled
things onto Ile and checked the reaction by Ninhydrin
and haven't found the need to double couple, but every
sequence is different.
Regards,
Steven R. Johnson, B.S. Chem.
Research Associate, Chemistry/Chem. Dev.
Biomeasure, Inc. Milford, Massachusetts, USA
--- Thomas Weber <thomas.weber@mssm.edu> wrote:
> Dear All,
> I plan to synthesize the following pepetide on a
> 431A using Fastmoc
> chemistry:
>
> GLFEAIEGFIENGWEGMIDGWYGC
>
> Do you think that capping at each step with acetic
> anhydride would be
> helpful ?
> Is there a general rule when to use capping ?
> any other suggestions ?
>
> Thanks
>
> Thomas
>
> --
> Dr. Thomas Weber
> Institute for Gene Therapy and Molecular Medicine
> Box 1496
> Mount Sinai School of Medicine
> 1425 Madison Avenue
> New York, NY 10029-6574
> United States of America
>
> Phone (office): (212) 659 8293
> Phone (lab): (212) 659 8299
> Fax: (212) 849 2437
> e-mail: thomas.weber@mssm.edu
>
>
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