May T, Rommelspacher H
Department of Neuropsychopharmacology, Free University, Berlin, Federal Republic of Germany.
J Neural Transm Suppl. 1994;41:69-73. doi: 10.1007/978-3-7091-9324-2_8.
Ethanol (ETOH) in vitro displays a competitive inhibition of human platelet MAO-B with a Ki of 270 +/- 30 mM. Lineweaver-Burk analyses with 6 substrate concentrations (5-160 microM kynuramine) in the presence or absence of 200 mM ETOH were performed with platelets of alcoholics before withdrawal (Alc day 1), one week (Alc day 8) and 3 months (Alc mon 3) after withdrawal as well as in control subjects without and after ETOH intake. In all groups the Km increases highly significantly (p < 0.001) but the Vmax is unchanged by the presence of ETOH in vitro supporting the view of a competitive inhibition in each group. The Vmax of Alc day 1 is significantly 25% decreased, of Alc day 8 unchanged and of Alc mon 3 nonsignificantly 19% decreased in comparison with the controls. The increase of the Km in the presence of 200 mM ETOH is significantly 15% reduced in Alc day 1 and 9% in Alc day 8 but unchanged in Alc mon 3 compared with the controls.
乙醇（ETOH）在体外对人血小板单胺氧化酶B（MAO - B）表现出竞争性抑制作用，其抑制常数（Ki）为270±30 mM。分别使用6种底物浓度（5 - 160 microM犬尿胺），在有或无200 mM ETOH存在的情况下，对戒酒前（饮酒者第1天）、戒酒1周（饮酒者第8天）、戒酒3个月（饮酒者第3个月）的饮酒者血小板以及未摄入ETOH和摄入ETOH后的对照受试者血小板进行Lineweaver - Burk分析。在所有组中，米氏常数（Km）均显著升高（p < 0.001），但体外存在ETOH时最大反应速度（Vmax）未改变，这支持了每组均存在竞争性抑制的观点。与对照组相比，饮酒者第1天的Vmax显著降低25%，饮酒者第8天的Vmax未改变，饮酒者第3个月的Vmax无显著降低，降低了19%。与对照组相比，在存在200 mM ETOH的情况下，饮酒者第1天的Km升高幅度显著降低15%，饮酒者第8天降低9%，而饮酒者第3个月的Km未改变。
