CHEMISTRY AND BIOCHEMISTRY OF ENERGY TRANSFER

能量转移的化学和生物化学

• 批准号: 3270187
• 负责人: WILLIAM P JENCKS
• 金额: $ 17.46万
• 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/3270187
• 关键词: acetaldehyde; adenosine triphosphate; adenosinetriphosphatase; calcium; chemical elimination; chemical reaction; chemical substitution; electron transport; 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ATP酶将按照以下目标进行检查。 (A)确定催化特异性变化的性质， 通常与ATP反应的两种酶的磷酸盐化合物 和磷酸盐，通过检查替代底物和磷酸盐 acceptoprs. (B)确定钾离子是否在一个或多个 催化循环的步骤。 (C)完成热力循环 通过测量钙离子结合的平衡常数 转化为磷酸酶。 (D)检查的性质缓慢解离 ATP来自酶-钙。 琥珀酰辅酶A：乙酰乙酸辅酶A转移酶 将分别使用辅酶A分子的一部分进行检查， 一起来表征10到12的速率加速度 通过与辅酶A的非共价相互作用。 的强度 水溶液中小分子之间的氢键将被检查 使用分光光度计技术，和偶极-偶极相互作用， 水的特征将通过测量添加的平衡常数来表征 取代的醇到取代的苯衍生物。 所报告的 从单分子到双分子反应机理的变化 将用不同的亲核试剂检查苯甲酰氯， 表征反应机理的变化。 一般酸催化 将研究向乙醛中加入水和醇， 确定该机制是否涉及协同催化。 反应 取代的甲氧基甲基衍生物与亲核试剂将在 试图跨越协调一致和循序渐进之间的“边界” 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， 将与消除机制的机制有关。 结构-反应性相关性将在以下反应中进行： 取代的磷酸盐，以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。