Browsing by Author "Tarhan, L"

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    Effects of antioxidant vitamins A, C, E and trace elements Cu, Se on CuZnSOD, GSH-Px, CAT and LPO levels in chicken erythrocytes
    Aydemir, T; Öztürk, R; Bozkaya, LA; Tarhan, L
    The biologically damaging effects of reactive oxygen species are controlled in vivo by a wide spectrum of antioxidant defence mechanisms. Dietary constituents of antioxidant vitamins and trace elements may play an important role in protecting against oxidant damage. The effects of supplementation of vitamins A, C, E and trace elements Cu and Se on the activities of antioxidant enzymes and lipid peroxide levels in chicken erythrocytes were investigated depend on the time. CuZnSOD activity and plasma Cu levels in the Cu group were increased by 39 and 37 per cent respectively. CuZnSOD activity in vitamin C groups was also increased by 20 per cent. The GSH-Px activity in Se, Se + E and Se + Ca groups was raised by 35, 46 and 69 per cent respectively. Also, the GSH-Px activity in the vitamin C group was increased by 33 per cent. Catalase activity in all of these groups was not significantly different when compared with controls (p < 0.01). The maximum decrease in LFO levels of 42 per cent was obtained for the Se + E group. Copyright (C) 2000 John Wiley & Sons, Ltd.
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    Effects of Se, Cu and Se plus vitamin E deficiency on the activities of CuZnSOD, GSH-Px, CAT and LPO levels in Chicken Erythrocytes
    Bozkaya, LA; Öztürk-Ürek, R; Aydemir, T; Tarhan, L
    Antioxidant enzymes and vitamins provide a defence against the damage of cells by reactive oxygen species in living systems. The effect of Cu, Se and vitamin E deficiencies on the antioxidant enzyme activities and lipid peroxide levels of chicken erythrocytes were investigated during 6 weeks of a depletion diet. CuZnSOD activity and the plasma Cu level of the Cu-deficient group which was fed a diet containing 0.2 mg Cu kg(-1) were reduced to 62 and 71% respectively. GSH-Px activity of the Se-deficient group was decreased by 46% but by 21% in the Cu-deficient group. CAT activity values of Se- and Cu-deficient groups were increased by 28 and 10% respectively. The maximum increase of LPO levels in erythrocyte membranes was observed as 32% for the Se + E-deficient group. The LPO level of the Cu-deficient group which had decreased CuZnSOD and GSH-Px activity, was also observed to be significantly increased when compared with the controls (p < 0.05). Copyright (C) 2001 John Wiley & Sons, Ltd.
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    Purification and partial characterisation of superoxide dismutase from chicken erythrocytes
    Aydemir, T; Tarhan, L
    Superoxide dismutase (SOD), which plays a very important role in protecting organisms from oxygen toxicity, was purified from chicken erythrocyte and partially characterised. Erythrocyte membranes were disintegrated via freeze-thaw methods in the presence of Triton X-100. Following ethanol precipitation, SOD-containing solution was applied to DEAE-cellulose and then Sephadex G-100 gel columns. Chicken erythrocyte SOD was purified 508-fold with a specific activity of 8,480 units per mg. The molecular weight was estimated to be 30.6 kDa +/- 0.4 by gel filtration. The enzyme was composed of two subunits of equal size and contained one atom of copper and one atom of zinc per molecule. Maximum SOD activity was observed between pH 7.0 to 9.0 at 25 degreesC. The enzyme has high thermal stability.