Aruoma O I, Halliwell B, Hoey B M, Butler J
Department of Biochemistry, University of London King's College, London, U.K.
Biochem J. 1988 Nov 15;256(1):251-5. doi: 10.1042/bj2560251.
It has been suggested that taurine, hypotaurine and their metabolic precursors (cysteic acid, cysteamine and cysteinesulphinic acid) might act as antioxidants in vivo. The rates of their reactions with the biologically important oxidants hydroxyl radical (.OH), superoxide radical (O2.-), hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) were studied. Their ability to inhibit iron-ion-dependent formation of .OH from H2O2 by chelating iron ions was also tested. Taurine does not react rapidly with O2.-, H2O2 or .OH, and the product of its reaction with HOCl is still sufficiently oxidizing to inactivate alpha 1-antiproteinase. Thus it seems unlikely that taurine functions as an antioxidant in vivo. Cysteic acid is also poorly reactive to the above oxidizing species. By contrast, hypotaurine is an excellent scavenger of .OH and HOCl and can interfere with iron-ion-dependent formation of .OH, although no reaction with O2.- or H2O2 could be detected within the limits of our assay techniques. Cysteamine is an excellent scavenger of .OH and HOCl; it also reacts with H2O2, but no reaction with O2.- could be measured within the limits of our assay techniques. It is concluded that cysteamine and hypotaurine are far more likely to act as antioxidants in vivo than is taurine, provided that they are present in sufficient concentration at sites of oxidant generation.
有人提出，牛磺酸、次牛磺酸及其代谢前体（半胱磺酸、半胱胺和半胱亚磺酸）可能在体内充当抗氧化剂。研究了它们与具有重要生物学意义的氧化剂羟基自由基（·OH）、超氧阴离子自由基（O₂⁻·）、过氧化氢（H₂O₂）和次氯酸（HOCl）的反应速率。还测试了它们通过螯合铁离子来抑制铁离子依赖的H₂O₂生成·OH的能力。牛磺酸与O₂⁻·、H₂O₂或·OH反应不迅速，其与HOCl反应的产物仍具有足够的氧化性，可使α1-抗蛋白酶失活。因此，牛磺酸似乎不太可能在体内发挥抗氧化剂的作用。半胱磺酸对上述氧化物种的反应性也很差。相比之下，次牛磺酸是·OH和HOCl的优秀清除剂，并且可以干扰铁离子依赖的·OH生成，尽管在我们的检测技术范围内未检测到其与O₂⁻·或H₂O₂的反应。半胱胺是·OH和HOCl的优秀清除剂；它也与H₂O₂反应，但在我们的检测技术范围内未检测到其与O₂⁻·的反应。结论是，只要半胱胺和次牛磺酸在氧化剂产生部位以足够的浓度存在，它们比牛磺酸更有可能在体内充当抗氧化剂。
