A mechanistic study of sialic acid mutarotation: Implications for mutarotase enzymes

Jefferson Chan, Gurtej Sandhu, Andrew J. Bennet

Research output: Contribution to journalArticle

Abstract

The mutarotation of N-acetylneuraminic acid (Neu5Ac) proceeds by four kinetically distinct pathways: (i) the acid-catalyzed reaction of neutral Neu5Ac; (ii) the spontaneous reaction of the carboxylic acid (the kinetically equivalent acid-catalyzed reaction on the anion being ruled out by the solvent deuterium kinetic isotope effect of 3.74 ± 0.68); (iii) a spontaneous, water-catalyzed, reaction of the anion; and (iv) a specific-base catalyzed reaction of the anion. The magnitude of the solvent kinetic isotope effect, kH2O/kD2O = 4.48 ± 0.74 is consistent with a ring-opening transition state in which a water molecule is deprotonating the anomeric hydroxyl group in concert with strengthening solvation of the ring oxygen atom. The mechanistic implications for Neu5Ac mutarotases are discussed.

Original languageEnglish (US)
Pages (from-to)4818-4822
Number of pages5
JournalOrganic and Biomolecular Chemistry
Volume9
Issue number13
DOIs
StatePublished - Jul 7 2011

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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