Levering P R, van Dijken J P, Veenhius M, Harder W
Arch Microbiol. 1981 Mar;129(1):72-80. doi: 10.1007/BF00417184.
A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine- and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formaldehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
从以甲胺作为唯一碳源的富集培养物中分离出一种兼性甲基营养细菌。它被初步鉴定为节杆菌属的一个种。在甲胺或乙胺上生长的细胞提取物含有高水平的胺氧化酶（E.C. 1.4.3）活性。在葡萄糖或胆碱上生长的细胞缺乏这种酶。该酶对伯胺的氧化导致过氧化氢的形成；因此，在甲胺和乙胺上生长的细胞中存在高水平的过氧化氢酶。通过向指数生长的细胞中添加20 mM氨基三唑（一种过氧化氢酶抑制剂），证明了过氧化氢酶在体内的重要性。这完全阻断了在甲胺上的生长，而在葡萄糖上的生长几乎没有受到影响。细胞化学研究表明，依赖甲胺的过氧化氢产生主要发生在细胞质膜的内陷处。甲胺氧化过程中产生的甲醛通过甲醛固定的RuMP循环的FBP变体进行同化。缺乏依赖NAD的甲醛和甲酸脱氢酶表明通过磷酸己酮糖合酶存在一条非线性的甲醛氧化途径。在各种底物上生长的该生物体的酶谱表明，胺氧化酶、过氧化氢酶和RuMP循环的酶的合成不受协同控制。
