Tsou M F, Chung J G, Wu L T, Cheng K S, Hung C F
Department of Clinical Medicine, China Medical College Hospital, Taichung, Taiwan, Republic of China.
Microbios. 1998;94(379):133-43.
N-acetyltransferase (NAT) activity was determined by incubation of purified Enterobacter aerogenes enzyme with 2-aminofluorene (2-AF) as the substrate, followed by high pressure liquid chromatography assays. The NAT activity from E. aerogenes was 0.58 +/- 0.08 nmol/min/mg protein for 2-AF. The values of apparent K(m) and Vmax were 0.72 +/- 0.14 mM and 2.45 +/- 0.29 nmol/min/mg protein, respectively, for 2-AF. The optimal pH value for the enzyme activity was 7.5 for the 2-AF tested. The optimal temperature for enzyme activity was 37 degrees C for the 2-AF substrate. The molecular weight of NAT from E. aerogenes was 44.9 kD. Among a series of divalent cations and salts, Zn2+, Ca2+, and Fe2+ were demonstrated to be the most potent protease inhibitors, and only ethylenediaminetetraacetic acid significantly protected the NAT. Iodoacetamide, in contrast to other agents, markedly inhibited NAT.
通过将纯化的产气肠杆菌酶与2-氨基芴（2-AF）作为底物一起孵育，随后进行高压液相色谱分析来测定N-乙酰转移酶（NAT）活性。产气肠杆菌的NAT对2-AF的活性为0.58±0.08 nmol/分钟/毫克蛋白。对于2-AF，表观K(m)和Vmax值分别为0.72±0.14 mM和2.45±0.29 nmol/分钟/毫克蛋白。所测试的2-AF的酶活性最佳pH值为7.5。对于2-AF底物，酶活性的最佳温度为37℃。产气肠杆菌NAT的分子量为44.9 kD。在一系列二价阳离子和盐中，Zn2+、Ca2+和Fe2+被证明是最有效的蛋白酶抑制剂，并且只有乙二胺四乙酸能显著保护NAT。与其他试剂相比，碘乙酰胺能显著抑制NAT。
