Does the Imidazole Bridge Break During Catalysis in Cu, Zn Superoxide Dismutase ? Judgement from XAFS and Crystallography

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

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Exogenous Sulphur Dioxide Induced Changes in Superoxide Dismutase, Peroxidation and Non- Protein SH Content in Mung Bean (Vigna Radiata) Seedlings

Journal of Chemistry Environmental Sciences and its Applications ◽

10.15415/jce.2015.12009 ◽

2015 ◽

Vol 1 (2) ◽

pp. 91-96

Author(s):

Rajeev Sharma ◽

Kawaljeet Kaur

Keyword(s):

Superoxide Dismutase ◽

Sulphur Dioxide ◽

Vigna Radiata ◽

Mung Bean ◽

Induced Changes

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Effect of 1,3,6-trimethyl-5-hydroxyuracil succinate on the antioxidant system and free-radical processes in the liver of adult and old rats treated with carbon tetrachloride

ZHurnal «Patologicheskaia fiziologiia i eksperimental`naia terapiia» ◽

10.25557/0031-2991.2018.03.55-59 ◽

2018 ◽

pp. 55-59

Author(s):

И.Д. Габдрахманова ◽

В.А. Мышкин ◽

Д.А. Еникеев ◽

А.Р. Гимадиева

Keyword(s):

Superoxide Dismutase ◽

Free Radical ◽

Carbon Tetrachloride ◽

Antioxidant System ◽

Complex Compound ◽

Antiradical Activity ◽

Conjugated Dienes ◽

Experimental Animals ◽

Old Rats ◽

Radical Processes

Цель исследования: изучение влияния сукцината 1,3,6-триметил-5-гидроксиурацила на антиоксидантную систему и свободнорадикальные процессы в печени взрослых и старых крыс при воздействии тетрахлорметана. Методика. В эксперименте использованы половозрелые животные 12-месячного возраста со средней массой 250 г и старые животные 24-месячного возраста, средней массой 395 г по 30 особей в каждой возрастной группе. Токсическое поражение печени вызывали подкожным введением 50%-ного масляного раствора тетрахлорметана (ТХМ, 2 г/кг) в течение 4 сут. Одновременно с токсикантом опытным животным внутрибрюшинно вводили водный раствор коплексного соединения сукцинат-1,3,6-триметил-5-гидроксиурацила (2,5 мг/100 г) 3 раза в сут. в течение первых 4 сут. и в течение последующих 3 сут. 1 раз в сут. Контролем служили опытные животные, которым вводили физиологический раствор в том же объеме. Изучали окислительную модификацию белков, перекисное окисление липидов (по содержанию ТБК-реагирующих продуктов, уровню гидроперекисей липидов и содержанию диеновых конъюгатов). Состояние антиоксидантной системы оценивали по активности ферментов супероксиддисмутазы, каталазы и глутатионпероксидазы, определяемых биохимическими методами. Антирадикальную активность комплексного соединения и его составляющих субстанций исследовали в модельной системе «этилбензол-ледяная уксусная кислота» с вычислением константы К - скорости взаимодействия перекисных радикалов с молекулами изучаемого соединения в сравнении с эталонным антиоксидантом-ионолом с витамином Е. Результаты. Сукцинат + 1,3,6-триметил-5-гидрокси-урацила существенно снижает токсическое действие ТХМ на печень взрослых и старых крыс, устраняет дисбаланс в системах свободнорадикального окисления белков у старых крыс, статистически значимо улучшает показатели свободнорадикального окисления (СРО) липидов в печени взрослых и старых крыс: снижает уровень продуктов ПОЛ - гидроперекисей, диеновых конъюгатов, ТБК-реагирующих продуктов, а также улучшает работу антиоксидантной системы (АОС), повышая активность каталазы, супероксиддисмутазы и глутатионпероксидазы. Установлена высокая антирадикальная активность изучаемого препарата сопоставимая с активностью эталонного антиоксиданта ионола. Заключение. Сукцинат и его производные способны выступать как индивидуальные вещества с непосредственным антирадикальным механизмом действия, а не только как стимуляторы ферментативных систем антиоксидантной защиты. Aim. To study the effect of a complex compound, 1,3,6-trimethyl-5-hydroxyuracil succinate, on the antioxidant system and free radical processes induced by carbon tetrachloride in the liver of adult and old rats. Methods. The study used sexually mature animals aged 12 months and weighing 250 g and old animals aged 24 months weighing 395 g (total n= 60, 30 rats in each age group). Toxic damage of liver was induced by subcutaneous injections of a 50% oil solution of carbon tetrachloride (CTC) at 2 g/kg for 4 days. Together with the toxicant, experimental animals were injected with a water solution of a complex compound, succinate 1,3,6-trimethyl-5-hydroxyuracil, at a dose of 2.5 mg/100 g, i.p., 3 times per day for the first 4 days and once daily for the following 3 days. Experimental animals were used as controls, which were administered saline in the same volume. Oxidative modifications of proteins, lipid peroxidation (by levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and conjugated dienes) were studied. Condition of the antioxidant system was evaluated by activities of superoxide dismutase, catalase, and glutathione peroxidase using biochemical methods. Antiradical activity of the complex compound and its components was studied in a model system of ethylbenzene-glacial acetic acid; the K7 constant of the rate of peroxide radical interaction with molecules of the studied compound was compared with the reference antioxidant ionol with vitamin E. Results. Succinate +1.3.6-trimethyl-5-hydroxyuracil, considerably reduced TXM hepatotoxicity in adult and old rats; removed the disbalance in free radical systems of protein oxidation in old rats; significantly improved indexes of free-radical oxidation (FRO) of hepatic lipids in adult and old rats; decreased levels of LP products, hydroperoxides, conjugated dienes, and TBARS, and enhanced performance of the antioxidant system (AOS) by increasing activities of catalase, superoxide dismutase, and glutathione peroxidase. The study demonstrated a high antiradical activity of the study drug comparable with the activity of the reference antioxidant, ionol. Сonclusion. Succinate and its derivatives can perform as individual substances with a direct antiradical mechanism of action rather than as stimulators of enzymic systems of antioxidant defence.

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State of the enzyme link of antioxidant protection in boys with hypoandrogenism

Problems of Uninterrupted Medical Training and Science ◽

10.31071/promedosvity2020.04.032 ◽

2020 ◽

Vol 40 (4) ◽

pp. 32-36

Author(s):

L. K. Parkhomenko ◽

◽

L. A. Strashok ◽

S. I. Turchina ◽

G. V. Kosovtsova ◽

...

Keyword(s):

Oxidative Stress ◽

Superoxide Dismutase ◽

Free Radical ◽

Glutathione Peroxidase ◽

Free Radical Oxidation ◽

Conjugated Dienes ◽

Delayed Puberty ◽

Control Group ◽

Antioxidant Protection ◽

Radical Oxidation

Recently, interest in the problem of free radical oxidation in biological membranes, which is directly related to both the normal functioning of cells and the occurrence, course and outcome of many pathological conditions, has increased again in clinical medicine. The aim was to determine the role and impact of antioxidant defense in boys with hypoandrogenism. The study involved 75 adolescents with hypoandrogenism aged 13–18 years, who underwent a complex of clinical and laboratory examinations. All patients were conducted complex of anthropometric research and determination of the degree of delayed puberty, laboratory and instrumental examination. Free radical oxidation was determined by the levels of malondialdehyde, conjugated dienes, carbonated proteins, superoxide dismutase and catalase in the serum, and restored glutathione and glutathione peroxidase in whole blood. Based on their determination, the coefficient of oxidative stress was calculated. Statistical processing of results was performed using parametric and nonparametric methods. The study of indicators of the free radical oxidation process found that adolescents with hypoandrogenism have multidirectional changes in the oxidation of proteins and lipids, namely: the level of conjugated dienes increases, the concentration of malondialdehyde remains at the level of the control group, and the level of carbonated proteins tends to decrease. As for the activity of antioxidant protection enzymes, a significant decrease in the level of glutathione peroxidase was detected, while the level of superoxide dismutase and catalase remained at the level of normative indicators. Oxidative stress accompanies and is one of the pathogenetic links in the formation or maintenance of the state of hypoandrogenism in boys. This requires the use of antioxidants, the complex of which must be selected individually.

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