Effect of inositol hexakisphosphate on the spectroscopic properties of the nitric oxide derivative of ferrous naturally glycated human hemoglobin HbA1c

Paolo Ascenzi, Gino Amiconi, Alberto Bertollini, Massimo Coletta, Maurizio Brunori, Alessandro Desideri, Martino Bolognesi, Massimo Castagnola

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of inositol hexakisphosphate (IHP) on the spectroscopic (EPR and absorbance) properties of the nitric oxide derivative of ferrous naturally glycated human hemoglobin HbA1c (HbA1cNO) has been investigated quantitatively. The results obtained show that 1) both in the absence and presence of IHP, the EPR and absorbance spectra of HbA1cNO show the same basic characteristics described for the nitrosyl derivative of ferrous HbA0, the nonglycated major component of human hemoglobin (HbA0NO); and 2) HbA1cNO binds IHP with an apparent dissociation equilibrium constant (θ{symbol} = 1.8 × 10-2 M), which is at least four orders of magnitude higher than that estimated for the polyphosphate interaction with HbA0NO (≤3 × 10-6 M). These data provide further independent evidence that interaction(s) of polyphosphates at the specific cleft between β-chains along the dyad-axis is sterically hindered in HbA1c by the presence of the two glucose residues covalently bound to the N-termini of β-chains, this finding being in agreement with the reduced effect of polyanions on HbA1c spectral and ligand-binding properties.

Original languageEnglish
Pages (from-to)19-24
Number of pages6
JournalJournal of Inorganic Biochemistry
Volume34
Issue number1
DOIs
Publication statusPublished - 1988

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

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