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From Proteopedia
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| - | Nickel Superoxide Dismutase (NiSOD) is the newest member in a class of enzymes that protects organisms from superoxide, a harmful free radical byproduct of aerobic metabolism. NiSOD reacts with two molecules of superoxide, to form O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> with rates occurring at or near the diffusion limit. | + | Nickel Superoxide Dismutase (NiSOD) is the newest member in a class of enzymes that protects organisms from oxidative stress caused by superoxide, a harmful free radical byproduct of aerobic metabolism. NiSOD reacts with two molecules of superoxide, to form O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> with rates occurring at or near the diffusion limit. During catalysis, the redox-active nickel center cycles between an oxidized and reduced state. This reaction is termed the pin pong mechanism and is shown below. |
:M<sup>(n + 1)</sup> + O<sub>2</sub><sup>•-</sup> → M<sup>n+</sup> + O<sub>2</sub> <br /> | :M<sup>(n + 1)</sup> + O<sub>2</sub><sup>•-</sup> → M<sup>n+</sup> + O<sub>2</sub> <br /> | ||
M<sup>n+</sup> + O<sub>2</sub><sup>•-</sup> + 2H<sup>+</sup> → M<sup>(n + 1)</sup> + H<sub>2</sub>O<sub>2</sub> <br /> | M<sup>n+</sup> + O<sub>2</sub><sup>•-</sup> + 2H<sup>+</sup> → M<sup>(n + 1)</sup> + H<sub>2</sub>O<sub>2</sub> <br /> | ||
————————————————— <br /> | ————————————————— <br /> | ||
| - | :2O<sub>2</sub><sup>•-</sup> + 2H<sup>+</sup> → O<sub>2</sub> + H<sub>2</sub>O<sub>2</sub> | + | :2O<sub>2</sub><sup>•-</sup> + 2H<sup>+</sup> → O<sub>2</sub> + H<sub>2</sub>O<sub>2</sub> <br /> |
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| + | NiSOD is distinct among SOD's for three reasons: | ||
| + | (1) NiSOD shares no sequence homology with the other known SOD's (Cu/ZnSOD, MnSOD, and FeSOD), (2) it has a distinct | ||
Revision as of 19:16, 11 December 2012
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Nickel Superoxide Dismutase (NiSOD) is the newest member in a class of enzymes that protects organisms from oxidative stress caused by superoxide, a harmful free radical byproduct of aerobic metabolism. NiSOD reacts with two molecules of superoxide, to form O2 and H2O2 with rates occurring at or near the diffusion limit. During catalysis, the redox-active nickel center cycles between an oxidized and reduced state. This reaction is termed the pin pong mechanism and is shown below.
- M(n + 1) + O2•- → Mn+ + O2
Mn+ + O2•- + 2H+ → M(n + 1) + H2O2
—————————————————
- 2O2•- + 2H+ → O2 + H2O2
NiSOD is distinct among SOD's for three reasons: (1) NiSOD shares no sequence homology with the other known SOD's (Cu/ZnSOD, MnSOD, and FeSOD), (2) it has a distinct
