At 02:53 PM 11/1/2000 -0600, John Harlan wrote:
>I am interested in finding out more about de-amidation. The preliminary look
>I have had in the literature suggests that this primarily occurs in proteins
>in flexible regions with -Asn-Gly- or -Asn-Ser- sequences. A succinimide
>intermediate is proposed, which then collapses about 75% to iso-aspartic acid
>and about 25% to aspartic acid. Similar reactions are noted for -Asp-Gly-
>and/ -Asp-Ser- sequences.
>
>It is also suggested that -Gln- can undergo this reaction. Are the same
>following residues (Ser/Gly) implicated? What is the proposed intermediate?
>
>Is there any precidence for this type of reaction to occur in sequences like
>-G-N-X-, where X is bulky?
>
>Any facts or lore regarding this would be greatly appreciated.
>
>John Harlan
>
>
>
>
John,
Have a look at "Deamidation and Isoaspartate Formation in Peptides and
Proteins" edited by Dana W. Aswad (1995) CRC press.
Regards,
Dan L. Crimmins
Washington University School of Medicine
Dept. Pathology/Division of Laboratory Medicine
660 S. Euclid Ave., Box 8118
St. Louis, MO 63110
Phone: 314-454-8514; Fax: 314-454-5208
e-mail: crimmins@labmed.wustl.edu
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