CHEMISTRY AND BIOCHEMISTRY OF ENERGY TRANSFER

能量转移的化学和生物化学

• 批准号: 3270190
• 负责人: WILLIAM P JENCKS
• 金额: $ 18.09万
• 依托单位: BRANDEIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-12-01 至 1988-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3270190
• 关键词: acetaldehyde; adenosine triphosphate; adenosinetriphosphatase; calcium; chemical elimination; chemical reaction; chemical substitution; electron transport; enzyme inhibitors; enzyme mechanism; enzyme structure; enzyme substrate; enzyme substrate complex; hydrogen bond; intermolecular interaction; phenylcarboxylate; phosphates; potassium; sodium; spectrometry; thermodynamics

The calcium-transporting ATPase will be examined with the following goals. (A) Determine the nature of the change in catalytic specificity toward phosphate compounds of two forms of the enzyme that normally react with ATP and phosphate, by examination of alternate substrates and phosphate acceptoprs. (B) Determine if potassium ion is occluded during one or more of the steps of the catalytic cycle. (C) Complete the thermodynamic cycle for the enzyme by measuring the equilibrium constant for binding of calcium to enzyme-phosphate. (D) Examine the nature of the slow dissociation of ATP from enzyme-calcium. Succinyl-CoA:acetoacetate coenzyme A transferase will be examined using portions of the coenzyme A molecule separately and together to characterize the rate acceleration of 10 to the 12 brought about by noncovalent interactions with coenzyme A. The strength of hydrogen bonds between small molecules in aqueous solution will be examined using a spectrophotometric technique, and dipole-diplole interactions in water will be characterized by measuring equilibrium constants for addition of substituted alcohols to substituted benzene derivatives. The reported change in mechanism from monomolecular to bimolecular for reactions of benzoyl chlorides will be examined with different nucleophiles to characterize the change in reaction mechanism. General acid catalysis of the addition of water and alcohols to acetaldehyde will be examined to determine if the mechanism involves concerted catalysis. Reactions of substituted methoxymethyl derivatives with nucleophiles will be examined in an attempt to cross the "borderline" between concerted and stepwise reaction mechanisms. The lifetimes of carbanion intermediates will be estimated using diffusion-controlled trapping reactions, and the lifetimes will be related to the mechanisms of elimination mechanisms. Structure-reactivity correlations will be carried out on reactions of substituted phosphates to determine if these reactions proceed through a concerted reaction mechanism rather than a metaphosphate intermediate.

钙转运ATPase将以下列目标进行检测。 (A)确定催化专一性发生变化的性质 通常与三磷酸腺苷反应的两种形式的酶的磷酸化合物 和磷酸盐，通过检查替代底物和磷酸盐 接受者。(B)确定在一个或多个过程中钾离子是否被遮挡 催化循环的步骤。(C)完成热力学循环 通过测定与钙结合的平衡常数对酶的影响 到酶-磷酸盐。(D)审查慢速离解的性质 来自酶钙的三磷酸腺苷。琥珀酰辅酶A：乙酰乙酸辅酶A转移酶 将分别使用辅酶A分子的部分和 一起来表征10到12的速度加速带来的 通过与辅酶A的非共价相互作用， 我们将研究水溶液中小分子之间的氢键。 使用分光光度技术，以及偶极-偶极相互作用 水将通过测量加成的平衡常数来表征。 从取代醇到取代苯衍生物。据报道， 从单分子反应机理到双分子反应机理的变化 将用不同的亲核剂对苯甲酰氯进行检测 表征反应机理的变化。普适的酸催化作用 在乙醛中加入水和醇将被检测到 确定该机制是否涉及协同催化。的反应 具有亲核性的取代甲氧基甲基衍生物将在 试图跨越协调与循序渐进之间的“分界线” 反应机理。碳负离子中间体的寿命将是 使用扩散控制的捕获反应估计的，以及寿命 将与消除机制有关的机制。 将对以下反应进行结构-反应性关联 取代磷酸盐来确定这些反应是否通过 协同反应机制，而不是偏磷酸盐中间体。