Enzymes superoxide dismutases and

All aerobic organisms contain substances that help prevent injury mediated by free radicals, and these include antioxidants such as a-tocopherol and the enzymes superoxide dismutase and glutathione peroxidase. When the protective effect of the antioxidants is overwhelmed by the production of reactive oxygen species, the intracellular milieu becomes oxidative, leading to a state known as oxidative stress (Halliwell and Gutteridge, 1999). Thus the balance between the generated free radicals and the efficiency of the protective antioxidant system determines the extent of cellular damage. 

In the muscle of active fish such as horse-mackerel and pickerel, the antiox-idative enzymes superoxide dismutase and catalase are more active than in the more sluggish scorpion fish (Rudneva-Titova, 1994 Rudneva-Titova and Zherko, 1994). 

The reader is referred to the following sources of further information on the specific cocatalytic enzymes superoxide dismutase, and the reduced form, alkahne phosphatases, nuclease Pl, purple acid phosphatase, amidohydrolase, leucine amtnopeptidase, general comments on the mechanisms of the phosphatases and aminopeptidases, and other cocatalytic zinc enzymes. ... 

Winn LM, Wells PG. Phenytoin-initiated DNA oxidation in murine embryo culture, and embryo protection by the antioxidative enzymes superoxide dismutase and catalase Evidence for reactive oxygen species-mediated DNA oxidation in the molecular mechanism of phenytoin teratogenicity. Mol Pharmacol 1995 48 112-20. 

Figure 13. The activity of key antioxidative enzymes (superoxide dismutase and glutathione peroxidase) in...

Figure 14. The activity of key antioxidative enzymes (superoxide dismutase and glutathione peroxidase) in pancreas cells of animals which are susceptible (rats) or are resistant (guinea pigs) to diabetogenic action of...

Figure 1. The activity of antioxidative enzymes — superoxide dismutase and glutathione peroxidase in the liver of rabbits and mini-pigs with experimental hypercholesterolemia.

Figure S.l The enzyme superoxide dismutase (SOD). SOD is a P structure comprising eight antiparallel P strands (a). In addition, SOD has two metal atoms, Cu and Zn (yellow circles), that participate in the catalytic action conversion of a superoxide radical to hydrogen peroxide and oxygen. The eight p strands are arranged around the surface of a barrel, which is viewed along the barrel axis in (b) and perpendicular to this axis in (c). [(a) Adapted from J.S. Richardson. The stmcture of SOD was determined in the laboratory of J.S. and D.R. Richardson, Duke University.)...

Superoxide is formed (reaction 1) in the red blood cell by the auto-oxidation of hemoglobin to methemo-globin (approximately 3% of hemoglobin in human red blood cells has been calculated to auto-oxidize per day) in other tissues, it is formed by the action of enzymes such as cytochrome P450 reductase and xanthine oxidase. When stimulated by contact with bacteria, neutrophils exhibit a respiratory burst (see below) and produce superoxide in a reaction catalyzed by NADPH oxidase (reaction 2). Superoxide spontaneously dismu-tates to form H2O2 and O2 however, the rate of this same reaction is speeded up tremendously by the action of the enzyme superoxide dismutase (reaction 3). Hydrogen peroxide is subject to a number of fates. The enzyme catalase, present in many types of cells, converts... 

It is possible that dietary flavonoids participate in the regulation of cellular function independent of their antioxidant properties. Other non-antioxidant direct effects reported include inhibition of prooxidant enzymes (xanthine oxidase, NAD(P)H oxidase, lipoxygenases), induction of antioxidant enzymes (superoxide dismutase, gluthathione peroxidase, glutathione S-transferase), and inhibition of redox-sensitive transcription factors. 

The enzyme superoxide dismutase regulates the level of superoxide by catalyzing conversion of superoxide to hydrogen peroxide and molecular oxygen. 

The process of the superoxide-dependent PCL that can be inhibited by enzyme superoxide dismutase (SOD) is shown in Figure 2. Luminol can be replaced by lucigenin. In this case, only the first maximum is detected. This variant of the system is useful for SOD activity measurements. The system is very sensitive and rugged therefore, it is even possible to perform the enzyme determination in whole blood [22],... 

C. carpio 10 during exposure for 96 h, significant alterations were recorded in lipid peroxidation rate, hemoglobin concentration, and erythrocyte antioxidant enzymes, that is, catalase, superoxide dismutase, and glutathione peroxidase activities 20... 

---