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CHEMISTRY AND BIOCHEMISTRY OF ENERGY TRANSFER

能量转移的化学和生物化学

基本信息

批准号：
2608743
负责人：
WILLIAM P JENCKS
金额：
$ 18.72万
依托单位：
BRANDEIS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1978
资助国家：
美国
起止时间：
1978-12-01 至 1999-11-30
项目状态：
已结题

项目摘要

Mechanisms of group transfer reactions and their catalysis will be studied in enzymic and nonenzymic systems and mechanisms for the conversion of chemical energy into work will be examined with the calcium-transporting ATPase of sarcoplasmic reticulum. This subject is important in the control and function of healthy and diseased muscle. The role of exact fixation and entropy loss in enzyme catalysis will be probed with partial and complete substrates for Coenzyme A transferase and by examining small changes in the size of substituents that are remote from the reacting groups of substrates. Rate and equilibrium constants for formation and breaking of hydrogen bonds in aqueous solution will be examined. The mechanism of calcium internalization and the internal calcium binding site of the calcium ATPase will be characterized. Phosphoryl transfer will be examined by a search for general base catalysis and for catalysis of the cleavage of phosphorylated pyridines by alkaline phosphatase. Acyl cyanides will be examined as substrates for chymotrypsin in an attempt to estimate the role of proton transfer to the leaving group in catalysis; concerted proton transfer to the leaving cyanide is not possible. The mechanism of proton transfer between electronegative atoms will be examined by determining Bronsted plots and isotope effects for general acid and general base catalysis of ester aminolysis involving diffusion-controlled proton transfer. Reactions of acyl halides will be examined to evaluate the importance of acylium ion intermediates and the possibility of a bimolecular substitution mechanism. The mechanism of proton removal from carbon will be studied using the sulfonium ion as activating group to determine if there are changes in transition state structure with changing reactant structure; these compounds are expected to have a small intrinsic barrier for proton transfer that may make such changes more readily detectible.

基团转移反应及其催化机制研究酶和非酶系统和机制将检查化学能转化为功肌浆网的钙转运 ATP 酶。这受试者对于健康和功能的控制和功能很重要患病的肌肉。精确固定和熵损失的作用酶催化作用将通过部分和完整的方式进行探讨辅酶 A 转移酶的底物并通过检查小远离的取代基的大小发生变化底物的反应基团。速率和平衡常数用于水溶液中氢键的形成和断裂将接受检查。钙内化机制钙 ATP 酶的内部钙结合位点是特点。磷酰基转移将通过搜索进行检查用于一般碱催化和用于裂解的催化吡啶被碱性磷酸酶磷酸化。酰基氰化物将作为胰凝乳蛋白酶的底物进行检查，试图估计质子转移到离去基团的作用催化;协同质子转移到离开的氰化物是不可能。质子之间的传递机制电负性原子将通过确定布朗斯台德来检查一般酸和一般碱的绘图和同位素效应涉及扩散控制的酯氨解催化质子转移。将检查酰基卤的反应评估酰基离子中间体的重要性和双分子取代机制的可能性。这将使用以下方法研究从碳中去除质子的机制锍离子作为活化基团以确定是否存在过渡态结构随反应物的变化而变化结构;这些化合物预计具有小的内在质子转移的障碍可能会使这种变化更多容易被检测到。