Tanaka A, Yasuhara S, Osumi M, Fukui S
Eur J Biochem. 1977 Oct 17;80(1):193-7. doi: 10.1111/j.1432-1033.1977.tb11871.x.
Yeast microbodies containing FAD-dependent alcohol oxidase, catalase and D-amino acid oxidase were isolated from methanol-grown cells of Kloeckera sp. 2201 and immobilized intact in matrices formed by a short-time illumination of photo-crosslinkable resin oligomers. The relative activities of catalase, alcohol oxidase and D-amino acid oxidase of the gel-entrapped microbodies were 36, 76 and 31% respectively as compared with those of free microbodies. Immobilization enhance d the stability of catalase to a certain degree, but not that of alcohol oxidase. The pH/activity profiles of catalase and alcohol oxidase of the entrapped organelles showed more narrow pH optima than those of the free counterparts. D-Amino acid oxidase in immobilized microbodies showed a somewhat higher Km value for D-alanine than that in free ones. Immobilized microbodies oxidized two moles of methanol to form two moles of formaldehyde with consumption of one mole of molecular oxygen. Addition of 3-amino-1,2,4-triazole, an inhibitor of catalase, reduced the formation of formaldehyde to half the amount without change in the amount of oxygen consumed, indicating the synergic action of alcohol oxidase and catalase in methanol oxidation in the microbodies of living yeast cells.
从甲醇培养的克鲁维酵母属2201细胞中分离出含有依赖黄素腺嘌呤二核苷酸的乙醇氧化酶、过氧化氢酶和D-氨基酸氧化酶的酵母微体,并将其完整固定在通过光交联树脂低聚物短时间光照形成的基质中。与游离微体相比,凝胶包埋微体中过氧化氢酶、乙醇氧化酶和D-氨基酸氧化酶的相对活性分别为36%、76%和31%。固定化在一定程度上提高了过氧化氢酶的稳定性,但对乙醇氧化酶的稳定性没有提高。包埋细胞器中过氧化氢酶和乙醇氧化酶的pH/活性曲线显示,其最适pH比游离对应物更窄。固定化微体中的D-氨基酸氧化酶对D-丙氨酸的Km值比游离微体中的略高。固定化微体将两摩尔甲醇氧化形成两摩尔甲醛,消耗一摩尔分子氧。添加过氧化氢酶抑制剂3-氨基-1,2,4-三唑可使甲醛生成量减少一半,而耗氧量不变,这表明乙醇氧化酶和过氧化氢酶在活酵母细胞微体中甲醇氧化过程中具有协同作用。