Taurine/a-ketoglutarate dioxygenase

The resonance Raman spectra of Fe(IV) complexes [(L)FeO]2+, where L = pentadentate pyridylamine ligands, include vFe=0 at 752 cm-1.298 Transient resonance Raman spectra of oxygen intermediates in the non-haem iron enzyme taurine/a-ketoglutarate dioxygenase, include characteristic bands at 812 (160)/787 (lsO) cm-1 and 583 (160)/555 (lsO) cm-1.299 Oxidised intermediates of cytochrome c oxidase give resonance Raman bands for vFe=0 showing that there are three different forms present.300... 

Price JC, Barr EW, Tirupati B, Bollinger JM Jr, Krebs C. The first direct characterization of a high-valent iron intermediate in the reaction of an alpha-ketoglutarate-dependent dioxygenase a high-spin FePV complex in taurine/alpha-ketoglutarate dioxygenase (TauD) from Escherichia coli. Biochemistry 2003 42 7497-7508. 

Eichhorn E, JR van der Ploeg, MA Kertesz, T Leisinger (1997) Characterization of an a-ketoglutarate-depen-dent taurine dioxygenase from Escherichia coli. J Biol Chem 272 23031-23036. 

Only since 2003 has there been spectroscopic evidence to support that monomeric, nonheme iron oxygenases cleave O2 and form Fe(IV)=0 species. These findings came from studies on taurine dioxygenase (TauD), a member of the Fe(If)/a-ketoglutarate (a-KG)-dependent hydroxylase superfamily of enzymes [48]. A generic mechanism proposed for hydroxylation is shown in Fig. 6.19 and includes an Fe(IV)=0 intermediate as the competent H-atom abstractor. 

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