SOD 1 superoxide dismutase

Postnatal (1-3 days) B6SJL-TgN(SODl-G93A)lGur mice overexpressing the human mutant transgene for superoxide dismutase 1 (SOD 1) and age-paired non-transgenic controls (wild-type, WT). The colony described by Gurney et al. [19] was derived from Jackson Laboratories (Bar Harbor, ME). 

Superoxide dismutase activity SOD Oxidative stress parameter Paraquat, PCDFs, HCB, BKME > Liver tissue 1-15... 

Ogawa et al. (1997) investigated the formation of H202 and the superoxide radical (02 ) in spinach (Spinacia oleracea) hypocotyls with the use of histochemical stains. Nitroblue tetrazolium (NBT) is used to detect 02 radicals. The colored reaction product formazan was only detected in the vascular tissue of developing spinach hypocotyls if CuZn-superoxide dismutase (CuZn-SOD E.C. 1.15.1.1) was inhibited by DDC... 

Figure 4.3 Effect of a variety of anti-free-radical interventions on reperfuslon-induced ventricular fibrillation In the Isolated perfused rat heart. Regional Ischaemia was induced by occluding a snare around the left anterior descending coronary artery and, after 10 min, hearts were reperfused by releasing the snare. Superoxide dismutase (SOD) (1 x 10° U/l), catalase (CAT) (1 X 10 U/l), mannitol (Mann) (50 mM), l-methlonlne (Methlon) (10 mM), glutathione (Glutath) (10 iiM) or desferrioxamlne (Deafer) (150 iim) were included throughout the experimental time course (n = 15/group). Redrawn with permission from Bernier et af. (1986).

Figure 4.8 Reduction of Na/K ATPase activity in isoiated guinea-pig hearts subjected to ischaemia/reperfusion and its prevention by various agents control non-ischaemic hearts (Nl) guinea-pig hearts subjected to global ischaemia for 2 h and subsequently reperfused for 1 h (IR). In other preparations, superoxide dismutase (SOD) 100 U/ml, catalase (CAT) 150 U/ml, dimethylsulphoxide (DMS) 50 mu, histidine (HIS) 10 mu, vitamin E (TOC)...

IV. Superoxide dismutase (EC 1.15.1.1) Within a cell the superoxide dismutases (SODs) constitute the first line of defense against ROS. Superoxide radical (02) is produced where an electron transport chain is present, as in mitochondria and chloroplasts, but 02 activation may occur in other subcellular locations such as glyoxysomes, peroxisomes, apoplast and the cytosol. Thus SODs are present in all these cellular locations, converting superoxide into hydrogen peroxide and water (i.e. copper/zinc SODs are typically found in the nuclei and cytosol of eukaryotic cells). 

Observations Table 1 shows the activity of the antioxidant enzymes of tomato roots after 72 h of exposure of allelochemical stress caused by S. deppei. Catalase (CAT) activity increases by 1.5 fold Ascorbate Peroxidase (APX) decreases 2.3 fold Glutathione reductase (GR) activity does not change with the treatment and Superoxide dismutase (SOD) decreases 1.3 fold. 

SOD in Figure 5 demonstrates the effect of superoxide dismutase on PCL. Its effect is characterized by an inhibition of the chemiluminescence intensity without having an impact on the lag phase. According to McCord and Frido-vich [27] (50% test signal inhibition), 1 activity unit in this system refers to approximately 100 ng of the enzyme preparation of the Sigma Co. 

The enzyme superoxide dismutase (SOD) occurs in three forms in mammalian systems (1) CuZnSOD (SOD1) found in the cytosol, (2) MnSOD (SOD2) found in mitochondria, and (3) CuZnSOD found in extracellular space (SOD3). Additionally, many bacterial SOD enzymes contain iron. SOD 1 has been discussed in detail... 

Several reports indicate the involvement of superoxide in the mediation of tolerance [67-69]. Based on these reports, a bifunctional superoxide dismutase-mimic NO donor was designed by Haj-Yehia s group [70]. The nitrate ester was incorporated into a nitroxide such as 3-hydroxymethyl-2,2,5,5-tetramethyl-l-pyrroHdinyloxy (HMP) by its conversion into 3-nitratomethyl-PROXYL (NMP) (Scheme 1.7). HMP is a stable, metal-independent, low-molecular weight SOD-mimic with excellent cell-permeability. So NMP is the first compound that can simultaneously generate NO and destroy superoxide. This may lead to novel nontolerance-inducing nitrovasodila-tors. 

Mn superoxide dismutases are found in both eubacteria and archaebacteria as well as in eukaryotes, where they are frequently found in mitochondria. They (Figure 16.1) have considerable structural homology to Fe SODs both are monomers of 200 amino acid and occur as dimers or tetramers, and their catalytic sites are also very similar. They both catalyse the two-step dismutation of superoxide anion and, like the Cu-Zn SODs, avoid the difficulty of overcoming electrostatic repulsion between two negatively charged superoxide anions by reacting with only one molecule at a time. As in the case of Cu-Zn SOD, a first molecule of superoxide reduces the oxidized (Mn3+) form of the enzyme, releasing... 

Thus, superoxide can react with almost all redox-active metal centers (Scheme 1). In general, going through similar redox reaction steps metal complexes can interact with superoxide either as catalysts for its dismutation (superoxide dismutase (SOD) mimetics), or in a stoichiometric manner (Scheme 1). 

Superoxide dismutase (SOD) catalyzes the reaction shown in Equation (1) ... 

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