SCIRP Mobile Website
Paper Submission

Why Us? >>

  • - Open Access
  • - Peer-reviewed
  • - Rapid publication
  • - Lifetime hosting
  • - Free indexing service
  • - Free promotion service
  • - More citations
  • - Search engine friendly

Free SCIRP Newsletters>>

Add your e-mail address to receive free newsletters from SCIRP.


Article citations


Radkiewicz, J.L., Zipse, H., Clarke, S. and Houk, K.N. (1996) Accelerated racemization of aspartic acid and asparagine residues via succinimide intermediates: An ab initio theoretical exploration of mechanism. Journal of the American Chemical Society, 118, 9148-9155.

has been cited by the following article:

  • TITLE: Two-water-assisted racemization of the succinimide intermediate formed in proteins. A computational model study

    AUTHORS: Ohgi Takahashi

    KEYWORDS: Aspartic Acid Residue; Racemization; Nonenzymatic Reaction; Succinimide; Water Catalysis; Enolization; Computational Chemistry; Density Functional Theory

    JOURNAL NAME: Health, Vol.5 No.12, December 18, 2013

    ABSTRACT: Racemization of aspartic acid (Asp) residues in proteins plays an important role in the molecular biology of aging. In the widely accepted mechanism of the Asp racemization, a succinimide (SI) intermediate is the species which actually undergo the direct racemization. In the present study, a two-water-assisted mechanism of the SI racemization was computationally investigated using a model compound in which an aminosuccinyl (Asu) residue is capped with acetyl and NMe groups on the N-and C-termini, respectively. The two water molecules catalyze the enolization of the Hα-Cα-C=O portion in the Asu residue by mediating proton relay from the α-carbon atom to the carboxyl oxygen atom. After the enolization, migration of the water molecules and conformational change lead to the mirror image of the initially formed enol two-water complex, and the racemization is completed by the following ketonization. The overall activation barrier (28.2 kcal·mol-1) corresponds to the enolization and ketonization steps, and falls within the available experimental activation energies (21.4-29.0 kcal·mol-1). Therefore, the two-water-assisted mechanism investigated here is plausible for the in vivo and in vitro racemization reactions of the SI intermediates formed in peptides and proteins.