Antioxidant enzymes activity

Punnonen, K., Puntala, A., Jansen, C.T. and Ahotupa, M. (1991a). UVB irradiation induces lipid peroxidation and reduces antioxidant enzyme activities in human keratinocytes in vitro. Acta Dermato-Venereol. 71,... 

Repeated periods of exercise reduce the likelihood of damage to skeletal muscle during subsequent bouts of the same form of exercise and this appears to be associated with an increase in the activity of muscle SOD (Higuchi et al. 1985), a reduced level of lipid peroxidation products during exercise in trained rats (Alessio and Goldfarb, 1988), and a modification of the concentration of antioxidants and activity of antioxidant enzymes in trained humans (Robertson etal., 1991). Packer and colleagues (Quintanilha etui., 1983 Packer, 1984) have also examined the exercise endurance of animals of modified antioxidant capacity and found that vitamin E-deficient rats have a reduced endurance capacity, while Amelink (1990) has reported that vitamin E-deficient rats have an increased amount of injury following treadmill exercise. 

A major contribution of the free-radical scavenging activity in blood plasma is attributable to the macro-molecular proteins (Wayner et al., 1985) of which albumin is a primary component and trapping agertt (Holt et al., 1984). Serum sulphydryl levels, primarily albumin-related, are decreased in subjects with rheumatoid complicated coalworkers pneumoconiosis, indicative of exacerbated inflammatory R.OM production (Thomas and Evans, 1975). Experimental asbestos inhalation in rats leads to an adaptive but evidendy insufficient response by an increase in endogenous antioxidant enzymes (Janssen etal., 1990). Protection of the vascular endothelium against iron-mediated ROM generation and injury is afforded by the iron sequestiant protein ferritin (Balia et al., 1992). 

Effects of Ethyl 2-Methylacetoacetate (EMA) on the Algal Antioxidant Enzymes Activity 150... 

Table 1 Antioxidant enzymes activities after 72 h treatment...

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. 

Jiang, M. and Zhang, J. (2002). Water stress-induced abscisic acid accumulation triggers the increased generation of reactive oxygen species and up-regulates the activities of antioxidant enzymes in maize leaves. Journal of Experimental Botany 53 2401-2410. 

Experiment 1. Evaluation of the effects of allelochemicals on the activity of algal antioxidant enzymes. 

In our previous research, we found that the antialgal allelochemical Ethyl 2-Methylacetoacetate (EMA) caused loss of cell membrane integrity. It hinted that EMA may cause a change in the membrane. It is reported that environmental stress may increase the concentration of ROS in plant cell. The excessive ROS may cause a decrease of antioxidation enzymes activity and lipid peroxidation. The effect of EMA on the activity of SOD and POD and lipid fatty acids of Chlorella pyrenoidosa, Chlorella vulagaris and Microcystis aeruginosa were evaluated to elucidate the mode of action of EMA. 

Mishra, N.P., Mishra, R.K. and Singhal, C.S. (1993). Changes in the activities of antioxidant enzymes during exposure of intact wheat leaves to strong visible light at different temperatures in the presence of protein synthesis inhibitors. Plant Physiology 102 903-910. 

Manevich, Y., Feinstein, S.I., and Fisher, A.B. (2004) Activation of the antioxidant enzyme 1-CYS perox-iredoxin requires glutathionylation mediated by heterodimerization with GST. Proc. Natl. Acad. Sci. USA 101, 3780-3785. 

All selenium-containing proteins and enzymes in animals, microorganisms and plants incorporate selenocysteine non-specifically105 or as part of Se-dependent antioxidant enzymes such as glutathione peroxidase, (EC 1.11.1.9) which has a Se-cysteine residue in its active site.116 120 An active form of Se, selenophosphate, is produced by selenophosphate synthetase in several bacteria. This active form is required for the production of Secys-tRNA, a precursor for Se-cysteine.121 In a similar vein, a Se-containing modified-tRNA nucleoside, 5-methylaminomethyl-2-selenouridine, encodes a selenouridine synthase which replaces sulfur in tRNA with selenium.122... 

Wang SY and Ballington JR. 2007. Free radical scavenging capacity and antioxidant enzyme activity in deerberry (Vaccinium stamineum L.). LWT Food Sci Technol 40(8) 1352—1361. 

Similar to lipids the oxidation of proteins has already been studied for more than 20 years. Before discussing the data on protein oxidation, it should be mentioned that many associated questions were already considered in previous chapters. For example, the oxidation of lipoproteins, which is closely connected with the problems of nonenzymatic lipid peroxidation was discussed in Chapter 25. Many questions on the interaction of superoxide and nitric oxide with enzymes including the inhibition of enzymatic activities of prooxidant and antioxidant enzymes are considered in Chapters 22 and 30. Therefore, the findings reported in those chapters should be taken into account for considering the data presented in this chapter. 

It is well known that most of the antioxidant enzymes and substrates can exhibit prooxidant activity under certain conditions, mainly because many stages of the reactions catalyzed by such enzymes are reversible. The question of possible prooxidant effects of SODs and the ability of SODs to react with the other substrates than superoxide have been studied for a long time. It is known that CuZnSOD is inactivated by the hydrogen peroxide formed. Hodgson and Fridovich [3] proposed that this inactivation depends on the reaction of hydrogen peroxide with the oxidized form Cu(II)ZnSOD yielding the bound hydroxyl radicals. 

---