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

FEBS Letters

Denisov, Ilia G¹  Ikeda-Saito, Masao²  Sligar, Stephen G¹  Yoshida, Tadashi³ 

[1] Departments of Biochemistry, Chemistry, and College of Medicine, University of Illinois, 116 Morrill Hall, 505 S. Goodwin Avenue, Urbana-Champaign, IL 61801, USA;Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106-4970, USA;Department of Biochemistry, Yamagata University School of Medicine, Yamagata 990-9585, Japan

关键词: Absorption spectroscopy;    Cryogenic reduction;    Heme oxygenase;    Reaction intermediates;    Radiolysis;    Reactive oxygen species;    HO;    heme oxygenase;    FeP-OOH;    hydroperoxo-ferric heme complex;    EPR;    electronic paramagnetic resonance;    ENDOR;    electron nuclear double resonance;   

DOI  :  10.1016/S0014-5793(02)03674-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown