PROSTAGLANDIN SYNTHASE - STRUCTURE AND FUNCTION

前列腺素H合酶是一种微粒体糖蛋白， 不同的催化活性：脂肪酸加氧酶和过氧化物酶。 的 脂肪酸加氧酶（环氧合酶）反应是第一个承诺的步骤 在前列腺素（PG）D2、PGE 2、PGF 2、PGI 2和 血栓素A2，其共同构成类花生酸的大部分。 至于 在其它脂肪酸加氧酶中，环氧合酶需要氢过氧化物来 催化活性 衍生自PGH 2的类二十烷酸参与了一个 多种生理和病理过程，包括 炎症、免疫监视、睡眠诱导、中风和心肌 梗塞 总的目标是确定的反应机制， PGH合酶的环氧合酶和过氧化物酶活性， 这些机制对类花生酸调控的影响 生物合成 具体目标是：a）鉴定和定量氧化还原中心， 合成酶并确定它们在催化中的作用; B）确定合成酶的活性， 通过氢过氧化物活化环氧合酶的机制; c） 确定脂肪酸结构影响的基础 环氧合酶的氢过氧化物活化剂需求; d）配制 环氧合酶和过氧化物酶的失活机制 e）表征亚基结构， 合酶中亚基的物理排列，以及它们的 影响催化活性。 所采用的方法包括：分析环氧合酶 和过氧化物酶活性;蛋白质和多肽纯化， 表征：蛋白水解酶和片段分析;金属 分析;紫外-可见分光光度法;磁性圆二色性; 电子顺磁共振

Prostaglandin H synthase is a microsomal glycoprotein which exhibits two distinct catalytic activities: a fatty acid oxygenase and peroxidase. The fatty acid oxygenase (cyclooxygenase) reaction is the first committed step in the biosynthesis of prostaglandin (PG) D2, PGE2, PGF2, PGI2 and thromboxane A2, which collectively make up the bulk of eicosanoids. As for other fatty acid oxygenases, the cyclooxygenase requires hydroperoxide for catalytic activity. The eicosanoids derived from PGH2 are involved in a wide variety of physiological and pathological processes including inlammation, immune surveillance, sleep induction, stroke, and myocardial infarction. The overall goal is to determine the reaction mechanisms of the cyclooxygenase and peroxidase activities of PGH synthase, and the implications of these mechanisms on the regulation of eicosanoid biosynthesis. The specific aims are to: a) identify and quantitate the redox centers in the synthase and establish their roles in catalysis; b) determine the mechanism of activation of the cyclooxygenase by hydroperoxide; c) determine the basis for the influence of fatty acid structure on the hydroperoxide activator requirement of the cyclooxygenase; d) formulate a mechanism for the inactivation of the cyclooxygenase and peroxidase activities during catalysis; and e) characterize the subunit structure and the physical arrangement of the subunits in the synthase, and their influence on catalytic activity. The methodologies to be employed include: analysis of the cyclooxygenase and peroxidase activities; protein and polypeptide purification and characterization: proteolytic digestions and fragment analysis; metal analysis; UV-vis spectrophotometry; magnetic circular dichroism; and electron paramagnetic resonance.