Unique Biradical Intermediate in the Mechanism of the Heme Enzyme Chlorite Dismutase.

ABSTRACT: The heme enzyme chlorite dismutase (Cld) catalyzes O-O bond formation as part of the conversion of the toxic chlorite (ClO₂ ^-) to chloride (Cl^-) and molecular oxygen (O₂). Enzymatic O-O bond formation is rare in nature, and therefore, the reaction mechanism of Cld is of great interest. Microsecond timescale pre-steady-state kinetic experiments employing Cld from Azospira oryzae (AoCld), the natural substrate chlorite, and the model substrate peracetic acid (PAA) reveal the formation of distinct intermediates. AoCld forms a complex with PAA rapidly, which is cleaved heterolytically to yield Compound I, which is sequentially converted to Compound II. In the presence of chlorite, AoCld forms an initial intermediate with s

SUBMITTER: Puschmann J 

PROVIDER: S-EPMC8650003 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature