Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detoxification of superoxide without production of H2O2: antioxidant
  activity of superoxide reductase complexed with ferrocyanide   The superoxide radical O(2)(-.) is a toxic by-product of oxygen metabolism.
Two O(2)(-.) detoxifying enzymes have been described so far, superoxide
dismutase and superoxide reductase (SOR), both forming H2O2 as a reaction
product. Recently, the SOR active site, a ferrous iron in a [Fe(2+) (N-His)(4)
(S-Cys)] pentacoordination, was shown to have the ability to form a complex
with the organometallic compound ferrocyanide. Here, we have investigated in
detail the reactivity of the SOR-ferrocyanide complex with O(2)(-.) by pulse
and gamma-ray radiolysis, infrared, and UV-visible spectroscopies. The complex
reacts very efficiently with O(2)(-.). However, the presence of the
ferrocyanide adduct markedly modifies the reaction mechanism of SOR, with the
formation of transient intermediates different from those observed for SOR
alone. A one-electron redox chemistry appears to be carried out by the
ferrocyanide moiety of the complex, whereas the SOR iron site remains in the
reduced state. Surprisingly, the toxic H2O2 species is no longer the reaction
product. Accordingly, in vivo experiments showed that formation of the
SOR-ferrocyanide complex increased the antioxidant capabilities of SOR
expressed in an Escherichia coli sodA sodB recA mutant strain. Altogether,
these data describe an unprecedented O(2)(-.) detoxification activity,
catalyzed by the SOR-ferrocyanide complex, which does not conduct to the
production of the toxic H2O2 species.

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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin