A fluorescence study of isofagomine protonation in β-glucosidase

Org Biomol Chem. 2015 Jun 21;13(23):6562-6. doi: 10.1039/c5ob00624d. Epub 2015 May 15.

Abstract

N-(10-Chloro-9-anthracenemethyl)isofagomine 5 and N-(10-chloro-9-anthracenemethyl)-1-deoxynojirimycin 6 were prepared, and their inhibition of almond β-glucosidase was measured. The isofagomine derivative 5 was found to be a potent inhibitor, while the 1-deoxynojirimycin derivative 6 displayed no inhibition at the concentrations investigated. Fluorescence spectroscopy of 5 with almond β-glucosidase at different pH values showed that the inhibitor nitrogen is not protonated when bound to the enzyme. Analysis of pH inhibition data confirmed that 5 binds as the amine to the enzyme's unprotonated dicarboxylate form. This is a radically different binding mode than has been observed with isofagomine and other iminosugars in the literature.

MeSH terms

  • Chemistry Techniques, Synthetic
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Glucosamine / analogs & derivatives
  • Glucosamine / chemical synthesis
  • Glucosamine / chemistry
  • Glucosamine / metabolism
  • Glucosamine / pharmacology
  • Hydrogen-Ion Concentration
  • Imino Pyranoses / chemical synthesis
  • Imino Pyranoses / chemistry*
  • Imino Pyranoses / metabolism
  • Imino Pyranoses / pharmacology
  • Kinetics
  • Protons
  • Prunus dulcis / enzymology
  • Spectrometry, Fluorescence
  • Structure-Activity Relationship
  • beta-Glucosidase / antagonists & inhibitors*
  • beta-Glucosidase / metabolism

Substances

  • 1-deoxy-nojirimycin
  • Enzyme Inhibitors
  • Imino Pyranoses
  • N-(10-chloro-9-anthracenemethyl)1-deoxynojirimycin
  • N-(10-chloro-9-anthracenemethyl)isofagomine
  • Protons
  • isofagomine
  • beta-Glucosidase
  • Glucosamine