Iron site structure of two irreversible hemichromes from human hemoglobin, untreated and oxidized to sulfoxide at MetD6(55)beta

Biochim Biophys Acta. 1996 May 2;1294(1):72-6. doi: 10.1016/0167-4838(95)00270-7.

Abstract

The Fe K-edge X-ray absorption near-edge structure (XANES) spectra of two irreversible human hemichromes, spontaneously formed from HbA and HbMetSO (a hemoglobin derivative, where MetD6(55)beta has been previously oxidized to sulfoxide by chloramine T) were determined. The results show that the hemichrome from HbMetSO is characterized by the distal histidyl imidazole moved within the bonding distance of the heme iron. Such structure is different from that of the hemichrome spontaneously produced from native human hemoglobin, which probably has a hydroxide group as sixth heme ligand.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Hemeproteins / chemistry*
  • Hemoglobin A / chemistry*
  • Hemoglobin A / metabolism
  • Humans
  • Iron / chemistry
  • Methemoglobin / analogs & derivatives
  • Methemoglobin / chemistry*
  • Oxidation-Reduction
  • Spectrum Analysis / methods
  • Sulfoxides / chemistry
  • X-Rays

Substances

  • Hemeproteins
  • Sulfoxides
  • hemichrome
  • Methemoglobin
  • Hemoglobin A
  • Iron