Enzymology of Peroxide Dismutation by a Manganese Catalase

植物乳杆菌产生含锰的 具有过氧化氢酶活性的酶，其被称为 假过氧化氢酶，以将其与血红素酶区分开 过氧化氢 假过氧化氢酶是亚基的寡聚体， 它含有两个锰原子， ESR测量参与一个双核簇。 催化活性受到羟胺和 在底物过氧化氢存在下的氟化物。 这些特征表明这种酶是一种近亲 和双核锰酶的可溶性同系物， 是绿色植物光合作用的放氧中心。 卡特博士已经将这种酶结晶化， 缺乏基质和氟化物的组合， 酶的失活和伴随的漂白 辅基 晶体的折射率很高 分辨率和他收集的三维原生 晶体强度数据到4.5A分辨率。 他现在计划 解出晶体结构并分析它们 它们的反应机理和它们与氧气的关系 进化中心

Lactobacillus plantarum produces a manganese-containing enzyme with catalase activity, which has been called pseudocatalase to distinguish it from the heme enzyme catalase. Pseudocatalase is an oligomer of subunits each of which contains two manganese atoms which have been shown by ESR measurements to participate in a binuclear cluster. Catalytic activity is inhibited by hydroxylamine and by fluoride in the presence of substrate, hydrogen peroxide. These features suggest that this enzyme is a close relative and a soluble homologue of the binuclear manganese enzyme in the oxygen evolving center of green plant photosynthesis. Dr. Carter has crystallized this enzyme in the presence and absence of a combination of substrate and fluoride that leads to inactivation of the enzyme and attendant bleaching of the prosthetic group. The crystals diffract to high resolution and he has collected three-dimensional native crystal intensity data to 4.5A resolution. He now plans to solve the crystal structures and to analyze them for clues to their reaction mechanism and their relationship to the oxygen evolving center.