Boehringer Mannheim's Asp-N insert is accurate. It definitely cuts before
Glu, mostly when the digest goes on too long or when the protease
concentration is too high. It is also my experience that certain glutamates
are more susceptible than others, although I haven't figured out why. Just
as B-M states in their product insert, use lower protease concentrations,
and hope that you don't have susceptible glutamates. (Sorry that I can't
comment on Cys; I've only tried Asp-N on nonreduced or S-alkylated
proteins.)
Mike Klein
Amgen, Inc.
> ----------
> From: dangott@mail.chem.tamu.edu[SMTP:dangott@mail.chem.tamu.edu]
> Sent: Friday, February 05, 1999 11:58 AM
> To: Recipients of ABRF List
> Subject: Asp-N
>
> Howdy y'all,
>
> We need to know about Asp-N specificity when used in solution digests of
> proteins. We see reports of cleavage after Asp, Glu and Cys
> (non-alkylated)
> and would like to know your comments. Our requirement would be strict
> fidelity to Asp. Any comments on suppliers are also welcome.
>
> Thanks for your help.
>
> Larry
>
>
>
>
> ********************************************************
> Larry Dangott, Ph.D.
> Protein Chemistry Laboratory
> Department of Chemistry
> Texas A&M University
> College Station, TX 77842-3012
> (409) 845-2965 Office
> (409) 845-2433 Lab
> (409) 845-8015 (FAX)
> dangott@mail.chem.tamu.edu
> quorum.tamu.edu/~proteins
>