Free radical superoxide dismutase

Free Radical Pathology Super-oxide Radical Superoxide Dismutases Irwin Fridovich 10, 257... 

The free radical superoxide, O2, reacts with nitric oxide, NO, to produce damaging peroxinitrite, OONO . This process has been postulated to be a mediator of ischemia-reperfusion injury as well as inflammatory and vascular diseases. Superoxide dismutases (SODs), enzymes discussed previously, are responsible for converting superoxide to hydrogen peroxide and oxygen. SODs are... 

Superoxide is a free radical form of oxygen (02 ) that is damaging to cells. Superoxide is scavenged by the enzyme superoxide dismutase used by neutrophils to destroy microbes in the body. 

Propyl gallate is an antioxidant. It protects against oxidation by hydrogen peroxide and oxygen free radicals in a catalytic manner similar to superoxide dismutase. 

Tissues are protected from oxygen toxicity caused by the superoxide free radical by the specific enzyme superoxide dismutase. 

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).

Geremia, E.C., Corsano, C., Bonomo, R., Giardinelli, R., Vanella, A. and Sichel, G. (1984). Eumelanins as free radical traps and superoxide dismutase activities in amphibia. Comp. Biochcm. Physiol. 79B, 67-69. 

Ono, M., Sekiya, C., Ohhira, M., Ohhiia, M., Namiki, M., Endo, Y., Susuki, K., Matsuda, Y. andTaniguchi, N. (1991). Elevated level of serum Mn-superoxide dismutase in patients with primary biliary cirrhosis possible involvement of free radicals in the pathogenesis of primary biliary cirrhosis. J. Lab. Clin. Med. 118, 476-483. 

Collier et al. (1990) extended their studies relating to oxidative stress and diabetes by demonstrating that the levels of several free-radical scavengers (red cell superoxide dismutase, plasma thiols) were significantly reduced in 22 type 2 diabetic patients (mean age 53 years) in comparison with 15 control subjects (mean age 51 years). No significant diflFerences in red cell lysate thiols or... 

Lipid peroxidation (see Fig. 17.2) is a chain reaction that can be attacked in many ways. The chain reaction can be inhibited by use of radical scavengers (chain termination). Initiation of the chain reaction can be blocked by either inhibiting synthesis. of reactive oxygen species (ROS) or by use of antioxidant enzymes like superoxide dismutase (SOD), complexes of SOD and catalase. Finally, agents that chelate iron can remove free iron and thus reduce Flaber-Weiss-mediated iron/oxygen injury. 

Somack R, Saifer MG, Williams LD (1991) Preparation of long-acting superoxide dismutase using high molecular weight polyethylene glycol (41,000-72,000 daltons). Free Radic Res Commun 12-13 553-562... 

J.M. McCord and I. Fridovich, Utility of superoxide dismutase in studying free radical reactions. II. Mechanism of the mediation of cytochrome c reduction by a variety of electron carriers. J. Biol. Chem. 245,1374-1377 (1970). 

In 1965 1967 a great interest has been attached to the possible role of free radicals in cancer after studies by Emanuel and his coworkers who reported the excessive production of free radicals in tumor cells (see, for example, Ref. [145]). On these grounds the authors suggested to apply antioxidant therapy for the treatment of cancer patients. Unfortunately, experimental proofs of overproduction of free radicals in cancer tissue turn out to be erroneous [146], A new interest in the role of free radicals in cancer development emerged after the discovery of superoxide and superoxide dismutases. 

Bruijn, L. I., Beal, M. F., Becher, M. W. et al. Elevated free nitrotyrosine levels, but not protein-bound nitrotyrosine or hydroxyl radicals, throughout amyotrophic lateral sclerosis (ALS)-like disease implicate tyrosine nitration as an aberrant in vivo property of one familial ALS-linked superoxide dismutase 1 mutant. Proc. Natl Acad. Sci. U.S.A. 94 7606-7611,1997. 

Copper is part of several essential enzymes including tyrosinase (melanin production), dopamine beta-hydroxylase (catecholamine production), copper-zinc superoxide dismutase (free radical detoxification), and cytochrome oxidase and ceruloplasmin (iron conversion) (Aaseth and Norseth 1986). All terrestrial animals contain copper as a constituent of cytochrome c oxidase, monophenol oxidase, plasma monoamine oxidase, and copper protein complexes (Schroeder et al. 1966). Excess copper causes a variety of toxic effects, including altered permeability of cellular membranes. The primary target for free cupric ions in the cellular membranes are thiol groups that reduce cupric (Cu+2) to cuprous (Cu+1) upon simultaneous oxidation to disulfides in the membrane. Cuprous ions are reoxidized to Cu+2 in the presence of molecular oxygen molecular oxygen is thereby converted to the toxic superoxide radical O2, which induces lipoperoxidation (Aaseth and Norseth 1986). 

Crosby, D.G. and R.K. Tucker. 1966. Toxicity of aquatic herbicides to Daphniamagna. Science 154 289-291. Darr, D.J., S. Yanni, and S.R. Pinnell. 1988. Protection of Chinese hamster ovary cells from paraquat-mediated cytotoxicity by a low molecular weight mimic of superoxide dismutase (DF-Mn). Free Radical Biol. Med. 4 357-363. 

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