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Cited by 1,311

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Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation.

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Geiger, T, Clarke, S·1987·Journal of Biological Chemistry

Abstract

Aspartyl and asparaginyl deamidation, isomerization, and racemization reactions have been studied in synthetic peptides to model these spontaneous processes that alter protein structure and function. We show here that the peptide L-Val-L-Tyr-L-Pro-L-Asn-Gly-L-Ala undergoes a rapid deamidation reaction with a half-life of only 1.4 days at 37 degrees C, pH 7.4, to give an aspartyl succinimide product. Under these conditions, the succinimide product can further react by hydrolysis (half-time, 2.3h) and by racemization (half-time, 19.5 h). The net product of the deamidation reaction is a mixture of L- and D-normal aspartyl and beta-transpeptidation (isoaspartyl) hexapeptides. Replacement of the asparagine residue by an aspartic acid residue results in a 34-fold decrease in the rate of succinimide formation. Significant racemization was found to accompany the deamidation and isomerization reactions, and most of this could be accounted for by the rapid racemization of the succinimide intermediate. Replacement of the glycyl residue in the asparagine-containing peptide with a bulky leucyl or prolyl residue results in a 33-50-fold decrease in the rate of degradation. Peptide cleavage products are observed when these Asn-Leu and Asn-Pro-containing peptides are incubated. Our studies indicate that both aspartic acid and asparagine residues may be hot spots for the nonenzymatic degradation of proteins, especially in cells such as erythrocytes and eye lens, where these macromolecules must function for periods of about 120 days and 80 years, respectively.

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Metadata

Authors
Geiger, T., & Clarke, S.
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
1987-01
Volume
262
Issue
2
Pages
785-794
ISSN
0021-9258 (ISSN-L)
OpenAlex
W1944789189
Cited by
1,311
References
25
FWCI
10.04
Type
journal article
Language
en
Open access
hybrid

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CoChat. (2026). Citation check: Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation. https://app.cochat.ai/papers/10.1016/s0021-9258(19)75855-4
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Geiger, T., & Clarke, S. (1987). Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation. Journal of Biological Chemistry. https://doi.org/10.1016/s0021-9258(19)75855-4

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