PROSTAGLANDIN SYNTHASE STRUCTURE AND FUNCTION

二十烷类化合物，一种含氧衍生物的集合 多不饱和脂肪酸，已被认为在 各种各样的生理和病理过程 包括炎症，免疫监测，睡眠诱导， 中风、心肌梗塞、荷尔蒙释放和致癌。 每一个生物合成的第一个承诺步骤 二十烷类化合物，将分子氧结合到脂肪中 酸，是由脂肪酸加氧酶催化的。最突出的 哺乳动物脂肪酸加氧酶是环辅酶的活性 前列腺素H合成酶，其产物随后被转化 前列腺素、血栓素类和前列环素。两个重要的因素 环氧合酶产生前列腺素的特性 是反应速度的反馈放大，由 产物过氧化氢和自催化失活。这些 其他脂肪酸加氧酶的特征是相同的，可能 在二十烷类化合物的生物合成调控中起重要作用。 前列腺素H合成酶可以大量分离 有关详细的物理特性，目前有更多 比其他哺乳动物脂肪酸加氧酶研究更方便。 总体目标是将催化行为和监管行为联系起来 对合成酶的反应机理，以及对合成酶的结构 合酶蛋白和天然的膜环境。这个 具体目的是分析纯绵羊合成酶：a) 描述过氧化物酶活性的机制 在合成酶中的存在增强了反应动力学 环氧合酶：(B)阐明自催化的机制 合酶失活；以及c)表征功能性 合成酶的结构域负责与其相互作用 活化剂、底物、抑制剂和磷脂。 将使用的方法学包括：环氧合酶分析 和过氧化物酶活性，以及对这些的计算机模拟 活性；蛋白质和多肽的纯化和 表征；UV-Vis分光光度；圆二色谱和 磁圆二向色性和电子顺磁共振。

The eicosanoids, a collection of oxygenated derivatives of polyunsaturated fatty acids, have been ascribed important roles in a broad variety of physiological and pathological processes including inflammation, immune surveillance, sleep induction, stroke, myocardial infarction, hormone release, and carcinogenesis. The first committed step in the biosynthesis of each of the eicosanoids, the incorporation of molecular oxygen into a fatty acid, is catalyzed by a fatty acid oxygenase. The most prominent mammalian fatty acid oxygenase is the cyclookygenase activity of prostaglandin H synthase, whose product is subsequently converted into prostaglandins, thromboxanes and prostacyclins. Two important characteristics of prostaglandin generation by the cyclooxygenase are the feedback amplification of the reaction rate, mediated by product hydroperoxide, and the self-catalyzed inactivation. These characteristics are shared by other fatty acid oxygenases and may be important in regulation of eicosanoid biosynthesis. Prostaglandin H synthase can be isolated in quantities sufficient for detailed physical characterization and currently is more convenient to study than other mammalian fatty acid oxygenases. The overall goal is to relate the catalytic and regulatory behavior of the synthase to its reaction mechanism, and to the structure of the synthase protein and the native membrane environment. The specific aims are to analyze the pure ovine synthase to: a) characterize the mechanism by which the peroxidase activity also present in the synthase enhances the reaction dynamics of the cyclooxygenase: (b) elucidate the mechanisms for self-catalyzed inactivation of the synthase; and c) characterize the functional domains of the synthase responsible for its interactions with activators, substrates, inhibitors, and phospholipid. The methodologies to be used include: analysis of cyclooxygenase and peroxidase activities, and computer simulation of these activities; protein and polypeptide purification and characterization; UV-vis spectrophotometry; circuLar dichroism and magnetic circular dichroism; and electron paramagnetic resonance.