Ehrig T, Bosron W F, Li T K
Department of Biochemistry, Indiana University School of Medicine, Indianapolis 46202.
Alcohol Alcohol. 1990;25(2-3):105-16. doi: 10.1093/oxfordjournals.alcalc.a044985.
The enzymes mainly responsible for ethanol degradation in humans are liver alcohol dehydrogenases (ADH) and aldehyde dehydrogenases (ALDH). Polymorphisms occur in both enzymes, with marked differences in the steady-state kinetic constants. The Km-values for ethanol of ADH isoenzymes relevant for alcohol degradation range from 49 microM to 36 microM, and the Vmax-values from 0.6 to 10 U/mg. Expression of an inactive form of the ALDH2 isoenzyme, the so-called Oriental variant, results in impaired acetaldehyde metabolizing capacity. The differences in ethanol and acetaldehyde metabolizing activities of allelic enzyme forms may be responsible in part for the large variation in the alcohol metabolism rate in humans. Interindividual differences in the isoenzyme pattern may contribute to the genetically determined predisposition for excessive alcohol intake.
在人体内，主要负责乙醇降解的酶是肝脏乙醇脱氢酶（ADH）和乙醛脱氢酶（ALDH）。这两种酶都存在多态性，其稳态动力学常数有显著差异。与酒精降解相关的ADH同工酶对乙醇的Km值范围为49微摩尔至36微摩尔，Vmax值为0.6至10 U/mg。ALDH2同工酶的无活性形式（即所谓的东方变体）的表达会导致乙醛代谢能力受损。等位酶形式在乙醇和乙醛代谢活性上的差异可能部分导致了人类酒精代谢率的巨大差异。同工酶模式的个体差异可能导致由基因决定的过量饮酒易感性。
