Cryogenic absorption spectra of hydroperoxo-ferric heme oxygenase, the active intermediate of enzymatic heme oxygenation

Ilia G. Denisov, Masao Ikeda-Saito, Tadashi Yoshida, Stephen G. Sligar

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Using radiolysis with 32P enriched phosphate as an internal source of ionizing radiation, the formation of hydroperoxo-ferric complex from oxy-ferrous precursor with a high yield was monitored at 77 K in heme oxygenase (HO) by means of optical absorption spectroscopy. Well-resolved absorption spectra (maxima at 421 nm, 530 nm, 557 nm) of hydroperoxo-ferric intermediate of this heme enzyme were measured in 70% glycerol/buffer frozen glasses. After annealing at 210-215 K this complex converts to the product complex, α-meso hydroxyheme-HO. No heme degradation products were formed in control experiments with ferric HO or other heme proteins.

Original languageEnglish
Pages (from-to)203-206
Number of pages4
JournalFEBS Letters
Volume532
Issue number1-2
DOIs
Publication statusPublished - 2002 Dec 4

Keywords

  • Absorption spectroscopy
  • Cryogenic reduction
  • Heme oxygenase
  • Radiolysis
  • Reaction intermediates
  • Reactive oxygen species

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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