Effect of flavin compounds on glutathione reductase activity: in vivo and in vitro studies

Beutler, Ernest

doi:10.1172/jci106162

Cited by 316 publications

(95 citation statements)

References 20 publications

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“…It is interesting that where other vitamins are concerned, there have been various reports of uptake into red cells and the consequent appearance of related forms in the cells (18)(19)(20)(21)(22)(23). However, it is not known whether the red cell converts these other vitamins to active forms which are also subsequently released into plasma.…”

Section: Discussionmentioning

confidence: 99%

Conversion of vitamin B6 compounds to active forms in the red blood cell

Anderson¹,

Fulford-Jones²,

Child³

et al. 1971

J. Clin. Invest.

104

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A B S T R A C T In studies with pyridoxine and other B6 compounds in blood, the active forms pyridoxal and pyridoxal phosphate were measured by differential assays using Lactobacillus casei. Red cell uptake of tritiated pyridoxine was also measured. A new metabolic pathway for conversion of pyridoxine to active forms was demonstrated in red cells.In vivo studies in normal subjects suggested that pyridoxine was taken up by red cells where it was converted to pyridoxal phosphate and then pyridoxal, followed by gradual release of a proportion of pyridoxal into plasma. In vitro incubation of pyridoxine with blood confirmed this observation.Increasing amounts of pyridoxine were taken up and converted as the amount added to blood was increased, and only very small numbers of red cells were needed to convert appreciable amounts. Conversion was markedly inhibited at temperatures lower than 370C, and stopped altogether at -20'C.Release of pyridoxal into plasma was always directly proportional to the amount of pyridoxal formed and to the volume of plasma present. That pyridoxal phosphate was not released into plasma was demonstrated in stored blood, for pyridoxine was converted mainly only as far as pyridoxal phosphate, probably due to inactivation of the phosphatase. Pyridoxal phosphate remained in the red cells.Pyridoxine was converted when incubated with washed red cells in saline or phosphate buffer suspension (0.08 M). In saline suspension, pyridoxal formed but was not released in the absence of plasma. In phosphate buffer suspension, pyridoxal phosphate was formed but was not changed to pyridoxal, probably due to inactivation of phosphatase by excess phosphate.This work was presented in part at the 8th International

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Section: Discussionmentioning

confidence: 99%

Conversion of vitamin B6 compounds to active forms in the red blood cell

Anderson¹,

Fulford-Jones²,

Child³

et al. 1971

J. Clin. Invest.

104

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“…The activity of GS-R was determined by the method of Beutler (1969), which was essentially the same as for GS-Px except that GSSG was added and GS-R was omitted. FAD was also added to this assay to ensure that maximum GS-R activity was generated.…”

Section: Biochemical Analysismentioning

confidence: 99%

Glutathione-linked enzymes in benign and malignant oesophageal tissue

et al. 1999

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Oxyradicals are involved in multiple mutational events and can contribute to the conversion of healthy cells to cancer cells. Glutathione (GSH) and the GSH-replenishing enzymes keep the antioxidant status of normal cells at a level where they can avert oxyradical derived mutations. The aim of this study was to determine whether in cancer cells the GSH-replenishing, GSH antioxidant and GSH-depleting enzymes were not at appropriate levels and therefore not able to protect cancer cells adequately against oxyradical-induced mutations. Cancer of the oesophagus was chosen since it is the most common gastrointestinal malignancy in South African Blacks. Biopsies and blood from 31 patients with cancer of the oesophagus and 29 non-cancer patients were assessed for these enzymes. The mean activity of the antioxidant and depleting enzyme GSH-peroxidase was elevated significantly by twofold in the cancer tissue compared to normal tissue. However, the activity of the replenishing enzyme GSSG-reductase and the level of the depleting enzyme GSH-s-transferase P1-isoenzyme were significantly reduced by 23% and 33% respectively. As in a previous paper we found that GSH was depleted and γ-glutamine transpeptidase was diminished in oesophageal cancer. There can be two reasons for GSH depletion. Firstly, elevated GSH–peroxidase will use more GSH in an attempt to cope with the excessive production of oxyradicals as revealed by elevated lipid peroxidation; this was, as shown by us before, elevated sixfold in oesophageal cancer. Secondly, if little replenishment of GSH occurred the level of GSH would become lower. This was confirmed by our findings that the activities of the replenishing enzymes were significantly diminished in oesophageal cancer tissue. Contrary to what was expected, the other depleting enzyme GSH-s-transferase P1 was not elevated in cancer tissue but was significantly lower. However, in the blood of the same patients it was significantly elevated. An explanation for this phenomenon is that, although the production of GST-P1 was enhanced in cancer, it did not show because it was rapidly extruded into the blood by an unknown mechanism operational only in cancer cells. © 1999 Cancer Research Campaign

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“…Генерацию пероксида водорода нейтрофилами при действии N-формил-метионил-лейцил-фенилаланина (fMLP) определяли флуорес-центным (скополетиновым) методом [19]. Кон-центрацию вторичных продуктов пероксидного окисления липидов (ПОл) -соединений, реаги-рующих с тиобарбитуровой кислотой (тБКрС) в плазме крови [20] и в составе лПНП и очень низкой плотности (лПОНП) [21], активность Cu, Zn-супероксиддисмутазы (СОД) крови [22], глу-татионпероксидазы [23] и глутатионредуктазы [24] в эритроцитах, каталазы [25] и суммарную антиоксидантную активность (аОа) [26] в плаз-ме крови оценивали спектрофотометрическими методами. Общий глутатион (GSHt) и глутати-он в окисленной форме (GSSG), содержащийся в эритроцитах, измеряли энзиматически [27].…”

Section: материалы и методыunclassified

Antioxidant status and glutathione redox potential of erythrocytes in patients with acute coronary syndrome

Buko¹,

Polonetsky²,

Мрочек³

et al. 2014

Ukr.Biochem.J.

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И зучение редокс-сигналирования и ре-докс-регуляции клеточных процессов становится все более весомым и распро-страненным для определения роли участников внутриклеточных и внеклеточных механизмов регуляции метаболизма, прежде всего в про-цессах свободно-радикального окисления, что основывается на способности биологических си-стем генерировать большее число нерадикаль-ных окислителей, нежели свободных радикалов [1,2]. Интенсивность окислительно-восстанови-тельных процессов отражает тиол-дисульфид-ный обмен, достигающий 0,5% SH-соединений в мин от общего пула клеточных тиолов [1]. Ключевыми эффекторами нерадикальных окис-лителей являются тиоредоксин, глутаредоксин, глутатион (GSH), ряд других сое динений, об-разующих редокс-пары (например, цистеин/ цистин), которые составляют суммарный ре-докс-потенциал (E h ) и, в конечном итоге, эф-фективный восстановительный потенциал [2].Современная методология позволяет оценить относительный редокс-статус от более восста-новленного до более окисленного в следую щем порядке: митохондрии > ядра > цитозоль > эн-доплазматический ретикулум > внеклеточное пространство [3]. Значения E h для окисленного глутатиона (GSSG) -300 мВ в митохондриях, от -220 до -260 мВ в цитозоле, -150 мВ в эндоплаз-матическом ретикулуме и -140 мВ в плазме или внеклеточном пространстве (для сравнения E h для цистина -80 мВ), составляя в эритроцитах величину, близкую к -150 мВ [4]. В соответствии с уравнением Нернста окислительно-восстано-вительный потенциал для пары 2GSH/GSSG ко-леблется в диапазоне от -260 мВ до -150 мВ [5]. Посредством транслокации и каталитических механизмов формируются редокс-цепи, с уча-стием которых осуществляются физиологиче-ская регуляция и генерализация окислительного стресса (ОС) [1,5,6]. еКСПерИмеНтальНі рОБОтИ

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Effect of flavin compounds on glutathione reductase activity: in vivo and in vitro studies

Cited by 316 publications

References 20 publications

Conversion of vitamin B6 compounds to active forms in the red blood cell

Conversion of vitamin B6 compounds to active forms in the red blood cell

Glutathione-linked enzymes in benign and malignant oesophageal tissue

Antioxidant status and glutathione redox potential of erythrocytes in patients with acute coronary syndrome

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