Kawaji A, Miki T, Takabatake E
Department of Toxicology, Setsunan University, Osaka, Japan.
Biol Pharm Bull. 1995 Dec;18(12):1657-9. doi: 10.1248/bpb.18.1657.
Flavin-containing monooxygenase (FMO) was partially purified from rat brain microsomes through two successive chromatographies on columns of DEAE Sepharose and 2',5'-ADP Sepharose. The specific activity, benzydamine N-oxidation of partially purified brain FMO, was 122-fold higher than that of microsomes. A single band of 60 kDa was recognized by Western blotting analysis with anti-rat liver FMO. The Km value of brain FMO for thiourea was 4-fold lower, but that for cysteamine was 10-fold higher than that of liver FMO. The enzymatic activity for n-octylamine was detected in neither brain nor liver FMO. Kinetic analysis for neurotoxins also revealed that Km values of brain FMO for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 1,2,3,4-tetrahydroisoquinoline (TIQ) and N-methyl TIQ (NMTIQ) were lower than those of liver FMO. These results indicate that rat brain FMO catalyzes several substrates of liver FMO involving neurotoxins, but it seems likely that the kinetic properties of brain FMO are somewhat different from those of liver FMO.
通过在二乙氨基乙基琼脂糖柱和2',5'-二磷酸腺苷琼脂糖柱上进行两次连续色谱法，从大鼠脑微粒体中部分纯化了含黄素单加氧酶（FMO）。部分纯化的脑FMO的比活性，即苄达明N-氧化活性，比微粒体高122倍。用抗大鼠肝脏FMO的蛋白质免疫印迹分析识别出一条60 kDa的单带。脑FMO对硫脲的Km值比肝脏FMO低4倍，但对半胱胺的Km值比肝脏FMO高10倍。在脑FMO和肝脏FMO中均未检测到对正辛胺的酶活性。对神经毒素的动力学分析还表明，脑FMO对1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPTP）、1,2,3,4-四氢异喹啉（TIQ）和N-甲基TIQ（NMTIQ）的Km值低于肝脏FMO。这些结果表明，大鼠脑FMO催化肝脏FMO的几种底物，包括神经毒素，但脑FMO的动力学特性似乎与肝脏FMO有所不同。
