Escherichia coli flavohemoglobin (HMP) is shown to be capable of catalyzing the reduction of several alkylhydroperoxide substrates into their corresponding alcohols using NADH as an electron donor. In particular, HMP possesses a high catalytic activity and a low Km toward cumyl, linoleic acid, and tert-butyl hydroperoxides, whereas it is a less efficient hydrogen peroxide scavenger. An analysis of UV-visible spectra during the stationary state reveals that at variance with classical peroxidases, HMP turns over in the ferrous state. In particular, an iron oxygen adduct intermediate whose spectrum is similar to that reported for the oxo-ferryl derivative in peroxidases (Compound II), has been identified during the catalysis of hydrogen peroxide reduction. This finding suggests that hydroperoxide cleavage occurs upon direct binding of a peroxide oxygen atom to the ferrous heme iron. Competitive inhibition of the alkylhydroperoxide reductase activity by carbon monoxide has also been observed, thus confirming that heme iron is directly involved in the catalytic mechanism of hydroperoxide reduction. The alkylhydroperoxide reductase activity taken together with the unique lipid binding properties of HMP suggests that this protein is most likely involved in the repair of the lipid membrane oxidative damage generated during oxidative/nitrosative stress.

Escherichia coli flavohemoglobin is an efficient alkylhydroperoxide reductase / Bonamore, Alessandra; Gentili, Patrizia; Ilari, Andrea; Schininà, M. Eugenia; Boffi, Alberto. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 278:25(2003), pp. 22272-22277. [10.1074/jbc.m301285200]

Escherichia coli flavohemoglobin is an efficient alkylhydroperoxide reductase

BONAMORE, ALESSANDRA;GENTILI, Patrizia;ILARI, ANDREA;BOFFI, Alberto
2003

Abstract

Escherichia coli flavohemoglobin (HMP) is shown to be capable of catalyzing the reduction of several alkylhydroperoxide substrates into their corresponding alcohols using NADH as an electron donor. In particular, HMP possesses a high catalytic activity and a low Km toward cumyl, linoleic acid, and tert-butyl hydroperoxides, whereas it is a less efficient hydrogen peroxide scavenger. An analysis of UV-visible spectra during the stationary state reveals that at variance with classical peroxidases, HMP turns over in the ferrous state. In particular, an iron oxygen adduct intermediate whose spectrum is similar to that reported for the oxo-ferryl derivative in peroxidases (Compound II), has been identified during the catalysis of hydrogen peroxide reduction. This finding suggests that hydroperoxide cleavage occurs upon direct binding of a peroxide oxygen atom to the ferrous heme iron. Competitive inhibition of the alkylhydroperoxide reductase activity by carbon monoxide has also been observed, thus confirming that heme iron is directly involved in the catalytic mechanism of hydroperoxide reduction. The alkylhydroperoxide reductase activity taken together with the unique lipid binding properties of HMP suggests that this protein is most likely involved in the repair of the lipid membrane oxidative damage generated during oxidative/nitrosative stress.
2003
01 Pubblicazione su rivista::01a Articolo in rivista
Escherichia coli flavohemoglobin is an efficient alkylhydroperoxide reductase / Bonamore, Alessandra; Gentili, Patrizia; Ilari, Andrea; Schininà, M. Eugenia; Boffi, Alberto. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 278:25(2003), pp. 22272-22277. [10.1074/jbc.m301285200]
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/250640
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 9
  • Scopus 42
  • ???jsp.display-item.citation.isi??? 43
social impact