Enzymology of Peroxide Dismutation by a Manganese Catalase

锰过氧化氢酶引起的过氧化物歧化的酶学

• 批准号: 8703699
• 负责人: Charles Carter
• 金额: $ 17.1万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-01 至 1991-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8703699&HistoricalAwards=false
• 关键词: Enzymology; Peroxide; Dismutation; Manganese; Catalase

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.

植物乳杆菌产生一种具有过氧化氢酶活性的含锰酶，为了区别于血红素酶过氧化氢酶，它被称为假过氧化氢酶。假焦糖酶是一种亚基的寡聚体，每个亚基都含有两个锰原子，ESR测量表明它们参与了一个双核簇合物。在底物过氧化氢存在下，羟胺和氟化物对催化活性有抑制作用。这些特征表明，该酶是绿色植物光合作用放氧中心的双核锰酶的亲缘关系和可溶性同系物。卡特博士已经在底物和氟化物的存在和不存在的情况下结晶了这种酶，这会导致酶的失活和伴随着假体基团的漂白。晶体的衍射率达到了高分辨率，他收集了分辨率为4.5A的三维自然晶体强度数据。他现在计划解决晶体结构，并分析它们，以寻找它们的反应机制以及它们与放氧中心的关系的线索。