Evidence for pentagalloyl glucose binding to human salivary α-amylase through aromatic amino acid residues

Gyöngyi Gyémánt, Ágnes Zajácz, Bálint Bécsi, Chandran Ragunath, Narayanan Ramasubbu, Ferenc Erdodi, Gyula Batta, Lili Kandra

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34 Scopus citations


We demonstrate here that pentagalloyl glucose (PGG), a main component of gallotannins, was an effective inhibitor of HSA and it exerted similar inhibitory potency to Aleppo tannin used in this study. The inhibition of HSA by PGG was found to be non-competitive and inhibitory constants of KEI = 2.6 μM and KESI = 3.9 μM were determined from Lineweaver-Burk secondary plots. PGG as a model compound for gallotannins was selected to study the inhibitory mechanism and to characterize the interaction of HSA with this type of molecules. Surface plasmon resonance (SPR) binding experiments confirmed the direct interaction of HSA and PGG, and it also established similar binding of Aleppo tannin to HSA. Saturation transfer difference (STD) experiment by NMR clearly demonstrated the aromatic rings of PGG may be involved in the interaction suggesting a possible stacking with the aromatic side chains of HSA. The role of aromatic amino acids of HSA in PGG binding was reinforced by kinetic studies with the W58L and Y151M mutants of HSA: the replacement of the active site aromatic amino acids with aliphatic ones decreased the PGG inhibition dramatically, which justified the importance of these residues in the interaction.

Original languageEnglish (US)
Pages (from-to)291-296
Number of pages6
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Issue number2
StatePublished - Feb 2009

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology


  • Human salivary α-amylase inhibition
  • NMR
  • Pentagalloyl glucose
  • Saturation transfer difference
  • Surface plasmon resonance


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