Langeland B T, McKinley-McKee J S
Institute of Biochemistry, University of Oslo, Norway.
Alcohol Alcohol. 1996 Jan;31(1):75-80. doi: 10.1093/oxfordjournals.alcalc.a008120.
The effects of disulfiram, its metabolite diethyldithiocarbamate and dithiodipyridine on alcohol metabolism of equine hepatic alcohol dehydrogenase (EC.1.1.1.1.) have been investigated. They were found to form enzyme-NAD(+)-inhibitor complexes which were competitive inhibitors of alcohol metabolism with dissociation constants (KEO,I) at pH 7.0 of 50 microM, 1.3 mM, and 260 microM, respectively. Acetate and vinegar behaved similarly in forming an inhibitory enzyme-NAD(+)-acetate ternary complex competitive with ethanol, with at pH 7.0 essentially identical dissociation constants of 4.0 mM and 3.8 mM, respectively. Disulfiram, diethyldithiocarbamate and dithiodipyridine were also found to exhibit affinity-labelling kinetics with liver alcohol dehydrogenase. The liver enzyme is chemically modified and inactivated in a similar manner by all three reagents via binary enzyme complexes with dissociation constants of 30 microM, 200 microM and 50 microM, respectively. Used as a protector against enzyme inactivation by DL-alpha-bromo-beta-(5-imidazolyl)-propionic acid, disulfiram, diethyl-dithiocarbamate and dithiodipyridine were found to form competitive binary enzyme complexes by binding to the active zinc site with KE,I values of 30 microM, 170 microM and 50 microM, respectively. The disulfiram and acetate binding to zinc results in the formation of binary and ternary complexes which inhibit alcohol metabolism at the enzyme level. Due to many unwanted side-effect), and the easy removal of its anti-drinking effects by drinking vinegar (vinegar effect), disulfiram may still be questioned as an effective drug against alcoholism.
已研究了双硫仑、其代谢产物二乙二硫代氨基甲酸盐和二硫代二吡啶对马肝乙醇脱氢酶（EC.1.1.1.1.）酒精代谢的影响。发现它们形成酶-NAD(+)-抑制剂复合物，这些复合物是酒精代谢的竞争性抑制剂，在pH 7.0时的解离常数（KEO,I）分别为50 microM、1.3 mM和260 microM。乙酸盐和醋在形成与乙醇竞争的抑制性酶-NAD(+)-乙酸盐三元复合物方面表现相似，在pH 7.0时，解离常数基本相同，分别为4.0 mM和3.8 mM。还发现双硫仑、二乙二硫代氨基甲酸盐和二硫代二吡啶对肝乙醇脱氢酶表现出亲和标记动力学。肝脏中的酶通过与解离常数分别为30 microM、200 microM和50 microM的二元酶复合物，被这三种试剂以类似方式进行化学修饰并失活。用作防止DL-α-溴-β-(5-咪唑基)-丙酸使酶失活的保护剂时，发现双硫仑、二乙二硫代氨基甲酸盐和二硫代二吡啶通过与活性锌位点结合形成竞争性二元酶复合物，其KE,I值分别为30 microM、170 microM和50 microM。双硫仑和乙酸盐与锌的结合导致形成二元和三元复合物，它们在酶水平上抑制酒精代谢。由于存在许多不良副作用，且饮用醋（醋效应）可轻易消除其戒酒效果，双硫仑作为一种有效的抗酒精中毒药物仍可能受到质疑。
