Chlorite reactivity with myoglobin: Analogy with peroxide and nitrite chemistry?

Chlorite reactivity with myoglobin: Analogy with peroxide and nitrite chemistry?
J Inorg Biochem. 2017 Apr 23;172:122-128
Authors: Bischin C, Mot A, Stefancu A, Leopold N, Hathazi D, Damian G, Silaghi-Dumitrescu R
Abstract
Stopped-flow UV-vis data allow for the first time direct spectroscopic detection of a ferryl species during the reaction of met myoglobin (Mb) with chlorite, analogous to what is observed in the reaction with peroxides. Ferryl is also observed in the reaction of oxy Mb+chlorite. A pathway involving Fe-O-O-ClO2 is explored by analogy with the Fe-O-O-NO and Fe-O-O-NO2 previously proposed as intermediates in the reactions of oxy globins with nitric oxide and nitrite, respectively. However, Fe-O-O-ClO2 is not detectable in these stopped-flow experiments and is in fact, unlike its nitrogenous congeners, predicted by density functional theory (DFT) to be impossible for a heme complex. Deoxy Mb reacts with chlorite faster than met - suggesting that, unlike with hydrogen peroxide (with which deoxy Mb reacts slower than met), binding of chlorite to the heme is not a rate-determining step (hence, most likely, an outer-sphere electron transfer mechanism); to correlate this, a Fe-O-Cl-O adduct was not observed experimentally for the met or for the deoxy reactions - even though prior DFT calculations suggest it to be feasible and detectable.
PMID: 28458145 [PubMed - as supplied by publisher]

Source: Journal of Inorganic Biochemistry - April 23, 2017 Category: Biochemistry Authors: Bischin C, Mot A, Stefancu A, Leopold N, Hathazi D, Damian G, Silaghi-Dumitrescu R Tags: J Inorg Biochem Source Type: research