URIC-ACID PROVIDES AN ANTIOXIDANT DEFENSE IN HUMANS AGAINST OXIDANT-CAUSED AND RADICAL-CAUSED AGING AND CANCER - A HYPOTHESIS
URIC-ACID PROVIDES AN ANTIOXIDANT DEFENSE IN HUMANS AGAINST OXIDANT-CAUSED AND RADICAL-CAUSED AGING AND CANCER - A HYPOTHESIS
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DOI：
10.1073/pnas.78.11.6858
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发表时间：
1981-01-01
期刊：
影响因子：
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通讯作者：
HOCHSTEIN, P
中科院分区：
文献类型：
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作者：
AMES, BN;CATHCART, R;HOCHSTEIN, P
在灵长类动物进化过程中，延长寿命和降低年龄特异性癌症发病率的一个主要因素可能是改善了对氧自由基的保护机制。这些保护系统之一可能是血浆尿酸，其水平在灵长类动物进化过程中作为一系列突变的结果显着增加。尿酸是一种强大的抗氧化剂，是单线态氧和自由基的清除剂。在生理浓度下，尿酸降低与血红蛋白过氧化反应形成的氧血红素氧化剂，保护红细胞免于脂质过氧化，保护红细胞免于导致裂解的过氧化损伤。在这些实验中，尿酸盐是和抗坏血酸一样有效的抗氧化剂。尿酸盐比脱氧核苷更容易被单氧氧化，并以相当的速率被羟基自由基破坏。人类血浆尿酸水平（约为0.1%）。300 .mu。M)的含量远远高于抗坏血酸水平，使其成为人类主要的抗氧化剂之一。先前文献中报道的关于尿酸盐的工作支持这些实验和解释，尽管这些发现没有在生理背景下进行讨论。
During primate evolution, a major factor in lengthening life-span and decreasing age-specific cancer rates may have been improved protective mechanisms against oxygen radicals. One of these protective systems may be plasma uric acid, the level of which increased markedly during primate evolution as a consequence of a series of mutations. Uric acid is a powerful antioxidant and is a scavenger of singlet oxygen and radicals. At physiological concentrations, urate reduces the oxo-heme oxidant formed by peroxide reaction with Hb, protects erythrocyte ghosts against lipid peroxidation and protects erythrocytes from peroxidative damage leading to lysis. Urate is about as effective an antioxidant as ascorbate in these experiments. Urate is much more easily oxidized than deoxynucleosides by single oxygen and is destroyed by hydroxyl radicals at a comparable rate. The plasma urate level in humans (.apprx. 300 .mu.m) is considerably higher than the ascorbate level, making it one of the major antioxidants in humans. Previous work on urate reported in the literature supports these experiments and interpretations although the findings were not discussed in a physiological context.