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J Am Chem Soc. 2004 Feb 4;126(4):1022-3.

Direct detection of oxygen intermediates in the non-heme Fe enzyme taurine/alpha-ketoglutarate dioxygenase.

Author information

  • 1Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA. denisp@cem.msu.edu

Abstract

The reaction of substrate-bound taurine/alpha-ketoglutarate dioxygenase with O2 has been studied using cryogenic continuous-flow spectroscopy. Transient absorption spectra acquired at -38 degrees C show an exponential decay of a 318-nm chromophore with an apparent rate of 1.3 s-1. The observed optical changes and their kinetics are consistent with the profile of an Fe(IV) species detected recently by Mössbauer spectroscopy (Price et al., Biochemistry 2003, 42, 7497-7508). Resonance Raman measurement upon excitation at 363.7 nm reveal at least two oxygen isotope-sensitive vibrations at 821/787 cm-1 and 583/555 cm-1 for 16O and 18O derivatives, respectively. An additional mode is likely to be obscured by an ethylene glycol vibration at 865 cm-1 and/or 1089 cm-1. The 821 cm-1 vibration is assigned to the stretching mode of Fe(IV)=O species on the basis of its frequency and isotopic shift amplitude. The 583 cm-1 band is likely to originate from an Fe-O2 precursor of the Fe(IV)=O species, although its structural details are unclear at present.

PMID:
14746461
DOI:
10.1021/ja039113j
[PubMed - indexed for MEDLINE]
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