Brömme H J, Weinandy R, Peschke D, Peschke E
Institute of Pathophysiology, Martin Luther University, Halle-Wittenberg, Germany.
Horm Metab Res. 2001 Feb;33(2):106-9. doi: 10.1055/s-2001-12402.
This in vitro study compares the frequency of redox cycling between alloxan and dialuric acid at different initial ratios of glutathione and alloxan. Alloxan oxidizes GSH to GSSG. The rate of GSH oxidation at a given initial GSH concentration of 2.0 mmol/L depends on the initial concentration of alloxan added. The higher the concentration of alloxan in relation to the initial concentration of GSH, the faster GSH oxidation proceeds, as well as oxygen consumption, and therefore, formation of reactive oxygen species. The highest rates of GSH oxidation, i.e. GSSG formation, were found at concentration ratios of between 2.0 mmol/L GSH and 0.2 and 0.04 mmol/L alloxan, respectively. Because 0.04 mmol/L alloxan oxidizes 2.0 mmol/L GSH completely, a frequency of at least 25 cycles between alloxan and dialuric acid within 3 hours can be assumed. During each redox cycle, two molecules of GSH are oxidized to one molecule of GSSG, and during each cycle one molecule of oxygen is reduced simultaneously to one molecule of hydrogen peroxide. In total, therefore, one molecule of alloxan oxidizes at least 50 molecules of GSH and forms about 25 molecules of hydrogen peroxide.
这项体外研究比较了在谷胱甘肽与四氧嘧啶不同初始比例下，四氧嘧啶和双脲酸之间氧化还原循环的频率。四氧嘧啶将谷胱甘肽（GSH）氧化为氧化型谷胱甘肽（GSSG）。在给定的2.0 mmol/L初始谷胱甘肽浓度下，谷胱甘肽氧化速率取决于添加的四氧嘧啶初始浓度。相对于谷胱甘肽初始浓度，四氧嘧啶浓度越高，谷胱甘肽氧化进行得越快，耗氧量以及活性氧的形成也是如此。在谷胱甘肽浓度为2.0 mmol/L与四氧嘧啶浓度分别为0.2 mmol/L和0.04 mmol/L的浓度比下，发现了最高的谷胱甘肽氧化速率，即氧化型谷胱甘肽的形成速率。由于0.04 mmol/L四氧嘧啶能将2.0 mmol/L谷胱甘肽完全氧化，因此可以假定在3小时内四氧嘧啶和双脲酸之间至少有25次循环。在每个氧化还原循环中，两分子谷胱甘肽被氧化为一分子氧化型谷胱甘肽，并且在每个循环中一分子氧气同时被还原为一分子过氧化氢。因此，总共一分子四氧嘧啶至少氧化50分子谷胱甘肽并形成约25分子过氧化氢。
