Novel Tripeptide Model of Nickel Superoxide Dismutase

A novel nickel-containing superoxide dismutase from Streptomyces spp.

A novel type of superoxide dismutase (SOD) was purified to apparent homogeneity from the cytosolic fractions of Streptomyces sp. IMSNU-1 and Strep. coelicolor ATCC 10147 respectively. Both enzymes were composed of four identical subunits of 13.4 kDa, were stable at pH 4.0-8.0 and up to 70 degrees C, and were inhibited by cyanide and H2O2 but little inhibited by azide. The atomic absorption anal...

Nickel superoxide dismutase structure and mechanism.

The 1.30 A resolution crystal structure of nickel superoxide dismutase (NiSOD) identifies a novel SOD fold, assembly, and Ni active site. NiSOD is a hexameric assembly of right-handed 4-helix bundles of up-down-up-down topology with N-terminal hooks chelating the active site Ni ions. This newly identified nine-residue Ni-hook structural motif (His-Cys-X-X-Pro-Cys-Gly-X-Tyr) provides almost all ...

Superoxide dismutase Superoxide dismutase

Kinetic study of nickel-thiolate oxygenation by hydrogen peroxide. Implications for nickel-containing superoxide dismutase.

The rate of metal-thiolate oxygenation by hydrogen peroxide has been measured for a model complex of nickel-containing superoxide dismutase (NiSOD) as 0.47 ± 0.03 M(-1) s(-1) at 303 K. Under typical synthetic conditions the reaction proceeds within seconds yielding S-oxygenate products. At biologically relevant H(2)O(2) concentrations, half-life times extend to several hours or days. The result...

The Effect of Normobaric Hyperoxia on Superoxide Dismutase Activity and Neurologic Deficits in Huntington Animal Model

Introduction: resent studies have been shown that normobaric hyperoxia (HO) can induce excitotoxicity and stress oxidative tolerance (ETT) in variety of organs such as brain. In this study, we examined the intermittent dose of normobaric hyperoxia (HO) on neurologic deficit, and superoxide dismutase activity in brain tissue of Huntington animal model. Method: The rats were divided to three...