ISOLATION OF PI-ALCOHOL DEHYDROGENASE OF HUMAN LIVER - IS IT A DETERMINANT OF ALCOHOLISM
ISOLATION OF PI-ALCOHOL DEHYDROGENASE OF HUMAN LIVER - IS IT A DETERMINANT OF ALCOHOLISM
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DOI：
10.1073/pnas.74.10.4378
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发表时间：
1977-01-01
影响因子：
11.1
通讯作者：
VALLEE, BL
中科院分区：
文献类型：
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作者：
LI, TK;BOSRON, WF;VALLEE, BL
人肝乙醇脱氢酶（酒精：NAD+氧化还原酶，EC 1.1.1.1），根据物理化学标准均质，最近才大量供应。到目前为止，人类酒精代谢的生化基础必须从其他物种（主要是马和酵母）的酶的特性和行为中推断出来。尽管最近的证据表明存在遗传倾向，但人类酗酒的生物决定因素仍然不清楚，需要加以描述。人类肝脏乙醇脱氢酶 (ADH) 的一种功能独特的形式被称为 II-ADH，它具有挑战性，因为迄今为止，它似乎是人类独有的。它对乙醇具有高 Km，并且对吡唑及其衍生物非常不敏感（表观 KI，500 μM），吡唑及其衍生物通常是有效的 ADH 抑制剂（KI，1 μM），这一特性是分离 II-ADH 的基础。亲和树脂 4-[3-(N-6-氨基己酰基)氨基丙基]吡唑-琼脂糖凝胶可结合所有其他已知形式的 ADH，但不结合 II-ADH，从而通过亲和色谱法选择性地将其分离。这导致了其与以前称为阳极带的酶形式的同一性的建立，其特征是对乙醇的高 Km（pH 7.5 时为 20 mm）。 II-ADH 对吡唑抑制的显着不敏感性也允许对其在肝乙醇氧化中的作用进行定量。 5 mM 乙醇几乎是所有其他形式的 ADH 的饱和浓度，II-ADH 对乙醇总氧化的贡献不到 15%。在令人陶醉的浓度下，例如 60 mM，它可以占肝脏总乙醇氧化率的 40%，表明这种酶形式在乙醇消除中看似独特的作用。迄今为止，II-ADH 的量因个体肝脏的不同而不同，并且比其他分子形式更加不稳定，其相互或独立的现象需要进一步研究。人类 II-ADH 的分离促进了认识和理解生化机制的努力，这些机制可能是酗酒和酒精相关疾病状态的生物决定因素，现在通常主要作为心理社会障碍来处理和管理。
Human liver alcohol dehydrogenase (alcohol: NAD+ oxidoreductase, EC 1.1.1.1), homogeneous by physicochemical criteria, was available in quantity only recently. Until now, the biochemical basis of human alcohol metabolism had to be extrapolated from the properties and behavior of enzymes from other species, primarily horses and yeast. The biological determinants of human alcoholism have remained obscure although recent evidence indicates a genetic predisposition, requiring delineation. A functionally distinct form of human liver alcohol dehydrogenase (ADH), which is designated II-ADH, is provocative since, thus far, it seems to be unique to human beings. It has a high Km for ethanol and is remarkably insensitive (apparent KI, 500 .mu.M) to pyrazole and its derivatives, which are usually potent ADH inhibitors (KI, 1 .mu.M), a property that is the basis for the isolation of II-ADH. The affinity resin 4-[3-(N-6-aminocaproyl)aminopropyl]pyrazole-Sepharose binds all other known forms of ADH but not II-ADH, thereby separating it selectively by affinity chromatography. This has led to the establishment of its identity with that enzyme form which was previously known as the anodic band and characterized by a high Km for ethanol (20 mm at pH 7.5). The remarkable insensitivity of II-ADH to pyrazole inhibition has also permitted quantitation of its role in hepatic ethanol oxidation. At 5 mM ethanol a saturating concentration for virtually all other forms of ADH, II-ADH contributes less than 15% to total ethanol oxidation. At intoxicating concentrations, e.g., 60 mM, it can account for as much as 40% of the total ethanol oxidation rate of liver, indicating a seemingly unique role for this enzyme form in ethanol elimination. Thus far the amount of II-ADH varies from liver to liver of individuals and is considerably more labile than the other molecular forms, phenomena whose inter- or independence requires further study. The isolation of human II-ADH advances efforts to recognize and understand biochemical mechanisms that may be biological determinants of alcoholism and alcohol-related disease states, now generally approached and managed largely as psychosocial disorders.