Cyclic guanidino-sugars with low pKa as transition-state analog inhibitors of glycosidases: Neutral instead of charged species are the active forms

Jin Hyun Jeong, Brion W. Murray, Shuichi Takayama, Chi Huey Wong

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

Cyclic guanidino-sugars with different pKa values are designed and synthesized as transition-state analog inhibitors of galactosidases. Characterization of these structures (7, 10, 12) reveals that 7 and 10 are in a pH-dependent equilibrium between a furanose form and a mixture of neutral and protonated tetrahydropyrimidine forms. In contrast, the O-linked guanidino-sugar 12 exists as the tetrahydropyrimidine forms above pH 5. The furanose- tetrahydropyrimidine equilibrium can thus be modulated with the appropriate N-substituent which affects the guanidino-sugar pKa value. Enzymatic inhibition by 7, 10, and 12 is also pH-dependent, indicating that the enzymes recognize the tetrahydropyrimidine form. Evidence is presented to support a dominant role for the uncharged form of the six-membered cyclic guanidino-sugar in the inhibition of galactosidases. Though the inhibition potency is moderate (Ki range 4-50 μM), the use of cyclic guanidino-sugars in the study provides new insights into the mechanism of inhibition of glycosidases.

Original languageEnglish
Pages (from-to)x1-4234
JournalJournal of the American Chemical Society
Volume118
Issue number18
DOIs
Publication statusPublished - 1996

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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