Olas Beata, Saluk-Juszczak Joanna, Nowak Pawel, Glowacki Rafal, Bald Edward, Wachowicz Barbara
Department of General Biochemistry, University of Lodz, Lodz, Poland.
Nutrition. 2007 Feb;23(2):164-71. doi: 10.1016/j.nut.2006.11.003.
The protective effects of D-glucaro 1,4-lactone (1,4-GL) against oxidative/nitrative protein damage (determined by parameters such as levels of protein carbonyl groups and nitrotyrosine residues) to human plasma treated with peroxynitrite (ONOO-) or hydroperoxide (H2O2) were studied in vitro. We also investigated the effects of 1,4-GL on the level of total free thiol groups and low-molecular-weight thiols (glutathione and homocysteine) in plasma treated with ONOO- (0.1 mM).
Levels of carbonyl groups and nitrotyrosine residues in human plasma proteins were measured by ELISA and a competition ELISA, respectively. High-performance liquid chromatography (HPLC) was used to analyze free thiols from plasma.
Exposure of plasma to ONOO- (0.1 mM) resulted in an increase of the level of carbonyl groups and nitrotyrosine residues in plasma proteins and in a distinct decrease in total thiols and low-molecular-weight thiols (glutathione and homocysteine) measured by high-performance liquid chromatography. In the presence of 1,4-GL (0.4-6.4 mM), a distinct decrease in carbonyl group formation and tyrosine nitration in plasma proteins and changes in plasma thiols caused by 0.1 mM of peroxynitrite were observed. Moreover, 1,4-GL inhibited plasma protein oxidation induced by H2O2 (2 mM).
The obtained results indicate that in vitro 1,4-GL has inhibitory effects on ONOO-- or hydroperoxide-mediated oxidative stress in human plasma and changes plasma redox thiol status. The mechanism of the antioxidative action of 1,4-GL present in plasma is not known yet.
在体外研究D - 葡萄糖二酸 -1,4 - 内酯（1,4 - GL）对经过氧亚硝酸盐（ONOO⁻）或过氧化氢（H₂O₂）处理的人血浆中氧化/硝化蛋白损伤（通过蛋白质羰基基团和硝基酪氨酸残基水平等参数确定）的保护作用。我们还研究了1,4 - GL对经0.1 mM ONOO⁻处理的血浆中总游离巯基基团和低分子量巯基（谷胱甘肽和同型半胱氨酸）水平的影响。
分别通过酶联免疫吸附测定（ELISA）和竞争ELISA法测定人血浆蛋白中的羰基基团和硝基酪氨酸残基水平。采用高效液相色谱法（HPLC）分析血浆中的游离巯基。
血浆暴露于0.1 mM ONOO⁻导致血浆蛋白中羰基基团和硝基酪氨酸残基水平升高，且通过高效液相色谱法测得的总巯基和低分子量巯基（谷胱甘肽和同型半胱氨酸）明显减少。在存在1,4 - GL（0.4 - 6.4 mM）的情况下，观察到血浆蛋白中羰基基团形成和酪氨酸硝化明显减少，以及0.1 mM过氧亚硝酸盐引起的血浆巯基变化。此外，1,4 - GL抑制了由2 mM H₂O₂诱导的血浆蛋白氧化。
所得结果表明，体外1,4 - GL对人血浆中ONOO⁻或过氧化氢介导的氧化应激具有抑制作用，并改变血浆氧化还原巯基状态。血浆中1,4 - GL的抗氧化作用机制尚不清楚。
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