Identification of a human stomach alcohol dehydrogenase with distinctive kinetic properties.
Identification of a human stomach alcohol dehydrogenase with distinctive kinetic properties.
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鉴定具有独特动力学特性的人胃乙醇脱氢酶。
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
Wu Cw
中科院分区：
文献类型：
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作者：
Shih;Wang Mf;Liao Cs;Chen Cm;Wu Cw
通过等电聚焦和动力学测定，在外科手术后的人胃粘膜中发现了一种新的乙醇脱氢酶，命名为MU-乙醇脱氢酶。该酶在琼脂糖等电聚焦凝胶上对I类(α、β、γ)和II类(Pi)乙醇脱氢酶具有阳极化作用。部分纯化的MU-醇脱氢酶以NAD+为辅因子，以长链醇为底物催化脂肪醇和芳香醇的氧化，底物呈桶形疏水结合袋。MU-乙醇脱氢酶在乙醇(18 MM)和NAD+(340微米)以及乙醇竞争性抑制剂4-甲基吡唑的高KI值(320微米)中脱颖而出。MU-乙醇脱氢酶可能占胃乙醇脱氢酶总活力的50%，在人类乙醇的首过代谢中起着重要作用。
A new form of alcohol dehydrogenase, designated mu-alcohol dehydrogenase, was identified in surgical human stomach mucosa by isoelectric focusing and kinetic determinations. This enzyme was anodic to class I (alpha, beta, gamma) and class II (pi) alcohol dehydrogenases on agarose isoelectric focusing gels. The partially purified mu-alcohol dehydrogenase, specifically using NAD+ as cofactor, catalyzed the oxidation of aliphatic and aromatic alcohols with long chain alcohols being better substrates, indicating a barrel-shape hydrophobic binding pocket for substrate. mu-Alcohol dehydrogenase stood out in high Km values for both ethanol (18 mM) and NAD+ (340 microM) as well as in high Ki value (320 microM) for 4-methylpyrazole, a competitive inhibitor for ethanol. mu-Alcohol dehydrogenase may account for up to 50% of total stomach alcohol dehydrogenase activity and appeared to play a significant role in first-pass metabolism of ethanol in human.