Chung J G
Department of Medicine, China Medical College, Taichung, Taiwan, Republic of China.
Drug Chem Toxicol. 1998 Aug;21(3):355-70. doi: 10.3109/01480549809002210.
Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) and p-aminobenzoic acid (PABA) as substrates were determined in Helicobacter pylori, collected from patients with peptic ulcers. The NAT activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. Inhibition of growth studies from H. pylori demonstrated that glycyrrhizic acid elicited dose-dependent bactericidal effect in H. pylori cultures, i.e.; the greater the concentration of glycyrrhizic acid, the greater the inhibition of growth of H. pylori. Cytosols or suspensions of H. pylori with and without selected concentrations of glycyrrhizic acid co-treatment showed different percentages of 2-AF and PABA acetylation. The data indicated that there was decreased NAT activity associated with increased glycyrrhizic acid in H. pylori cytosols and intact cells. For the cytosol and intact bacteria examinations, the apparent values of Km and Vmax were decreased after co-treated with 80 M glycyrrhizic acid. This report is the first demonstration of glycyrrhizic acid inhibition of arylamine NAT activity and glycyrrhizic acid inhibition of growth in the bacterium H. pylori.
以2-氨基芴（2-AF）和对氨基苯甲酸（PABA）为底物，测定了从消化性溃疡患者体内分离出的幽门螺杆菌中的芳胺N-乙酰基转移酶（NAT）活性。采用乙酰辅酶A循环分析和高压液相色谱法测定NAT活性。幽门螺杆菌生长抑制研究表明，甘草酸在幽门螺杆菌培养物中产生剂量依赖性杀菌作用，即甘草酸浓度越高，对幽门螺杆菌生长的抑制作用越强。经选定浓度的甘草酸共同处理和未处理的幽门螺杆菌细胞溶质或悬浮液显示出不同百分比的2-AF和PABA乙酰化。数据表明，幽门螺杆菌细胞溶质和完整细胞中，随着甘草酸含量增加，NAT活性降低。对于细胞溶质和完整细菌检测，经80μM甘草酸共同处理后，Km和Vmax的表观值降低。本报告首次证明了甘草酸对芳胺NAT活性的抑制作用以及甘草酸对幽门螺杆菌生长的抑制作用。
