Wu L T, Chung J G
Department of Microbiology, China Medical College, Taiwan, Republic of China.
Anticancer Res. 1998 Sep-Oct;18(5A):3481-6.
Arylamine N-acetyltransferase (NAT) activity in a human liver tumor (heptoma) cell line was inhibited by vitamin C. Using high performance liquid chromatography, NAT activity on the acetylation of 2-aminofluorene and p-aminobenzoic acid was examined. Two assay systems were performed, one with cellular cytosols, the other with intact liver tumor cell suspensions. The NAT activity in a human liver tumor cell line was inhibited by vitamin C in a dose-dependent manner in both types of examined system: i.e. the greater the concentration of vitamin C in the reaction, the greater the inhibition of NAT activities in both systems examined. The data also indicated that vitamin C decreased the apparent Km and Vmax of NAT enzymes from human liver tumor cells in both systems examined. This report is the first demonstration which showed vitamin C effect on human liver tumor cell NAT activity.
维生素C可抑制人肝癌细胞系中的芳胺N - 乙酰基转移酶（NAT）活性。采用高效液相色谱法，检测了NAT对2 - 氨基芴和对氨基苯甲酸乙酰化的活性。进行了两种检测系统，一种是细胞胞质溶胶系统，另一种是完整肝癌细胞悬液系统。在两种检测系统中，人肝癌细胞系中的NAT活性均受到维生素C的剂量依赖性抑制：即在反应中维生素C浓度越高，两种检测系统中NAT活性的抑制作用越强。数据还表明，在两种检测系统中，维生素C均降低了人肝癌细胞NAT酶的表观Km和Vmax。本报告首次证明了维生素C对人肝癌细胞NAT活性的影响。
