Evidence for Hydrogen Abstraction from C1 of Taurine by the High-Spin Fe(IV) Intermediate Detected during Oxygen Activation by Taurine:α -Ketoglutarate Dioxygenase (TauD)

The Fe(II)- and α-ketoglutarate-dependent dioxygenases catalyze hydroxylation reactions of considerable biomedical and environmental significance. Recently, the first oxidized iron intermediate in the reaction of a member of this family, taurine:α-ketoglutarate dioxygenase (TauD), was detected and shown to be a high-spin, formally Fe(IV) complex. The demonstration in this study that decay of the Fe(IV) complex is ∼30-fold slower when it is formed in the presence of 1-[²H]₂-taurine provides evidence that the intermediate abstracts hydrogen from C1, the site of hydroxylation, and suggests that quantum-mechanical tunneling may contribute to C1-H cleavage.