Bora P S, Spilburg C A, Lange L G
Department of Medicine, Jewish Hospital of St. Louis, Washington University Medical Center 63110.
J Clin Invest. 1989 Dec;84(6):1942-6. doi: 10.1172/JCI114382.
Nonoxidative alcohol metabolism catalyzed by fatty acid ethyl ester (FAEE) synthases may contribute to extrahepatic injury resulting from alcohol abuse. Unlike rabbit myocardial FAEE synthase, that from human heart has a satellite minor synthase (I) eluting from DEAE cellulose at a conductivity of 5 mS. Synthase I was purified 1,118-fold to homogeneity by sequential gel permeation, hydrophobic interaction, and Superose-12 fast-protein liquid chromatographies. SDS-PAGE showed a single polypeptide with a molecular mass of 26 kD and gel permeation chromatography indicated a molecular mass of 52 kD for the active enzyme. Homogeneous synthase I catalyzed ethyl ester synthesis at highest rates with unsaturated octadecanoic fatty acid substrates. The amino acid composition of synthase I was highly homologous to that of human myocardial major synthase, recently identified as an acidic glutathione (GSH) S-transferase. Antibody raised against homogeneous human heart major synthase cross-reacted with the 26-kD synthase I. FAEE synthase co-chromatographed with GSH S-transferase on DEAE cellulose, Sephadex G-100 and S-hexylglutathione agarose, and also displayed GSH S-transferase activity in catalyzing the conjugation of GSH with nitrobenzene-containing carcinogens. Thus, human myocardium contains a satellite peak of FAEE synthase activity and it is a neutral GSH S-transferase.
由脂肪酸乙酯（FAEE）合酶催化的非氧化酒精代谢可能导致酒精滥用引起的肝外损伤。与兔心肌FAEE合酶不同，人心脏的FAEE合酶有一个卫星次要合酶（I），在5 mS的电导率下从DEAE纤维素上洗脱下来。通过连续的凝胶渗透、疏水相互作用和Superose-12快速蛋白质液相色谱法，合酶I被纯化了1118倍达到同质。SDS-PAGE显示有一条分子量为26 kD的单一多肽，凝胶渗透色谱法表明活性酶的分子量为52 kD。同质的合酶I以不饱和十八烷酸底物催化乙酯合成的速率最高。合酶I的氨基酸组成与最近被鉴定为酸性谷胱甘肽（GSH）S-转移酶的人心肌主要合酶高度同源。针对同质人心肌主要合酶产生的抗体与26-kD的合酶I发生交叉反应。FAEE合酶在DEAE纤维素、Sephadex G-100和S-己基谷胱甘肽琼脂糖上与GSH S-转移酶共色谱，并且在催化GSH与含硝基苯的致癌物结合时也表现出GSH S-转移酶活性。因此，人心肌含有FAEE合酶活性的一个卫星峰，并且它是一种中性GSH S-转移酶。
