等温滴定量热法幻灯片.pptVIP

等温滴定微量热法(Isothermal Titration Calorimetry, ITC) 林杰 ITC Isothermal titration calorimetry (ITC) is used to measure the heat adsorbed or released during changes in the composition of a system undergoing a titration process. 等温滴定量热技术（ITC）是一种监测由结合成分的添加而起始的任 何化学反应的热力学技术，即用一种反应物滴定另一种反应物，随着加入滴定剂的数量的变化，测量反应体系温度的变化 history built in the secondhalf of the 1960s to study chemical reactions. During the1970s, the sensitivity of instruments was in the range of mJ, and other first applications were developed such as the study of (metal + ligand) complexes [8] and the adsorption of aromatic compounds by molecular sieves . In 1980s, the sensitivity was improved to μJ range. New applications in the 1980s were related to biology,biochemistry and physical chemistry such as the study of ligand binding processes and micelle formation history Since the beginning of 1990s, the number of published papers related to ‘‘isothermal titration calorimetry ’’ has symptomatically increased due to rapid diffusion of new commercial calorimeters in the scientific community. history During the decade of 1990, isothermal titration calorimetry has evolved from a specialist method to a widely used technique . During the 2000’s, isothermal titration calorimetry was widely employed in the design and discovery of drugs and in addition to this, in this last decade an isothermal titration calorimeter with open cell was employed for the study of liquid mixtures . ITC ITC可以直接测量焓变△H，结合常数Ka，而不对反应体系产生影响，也不引入修饰基团，因此测得的结果更加可信 流程 模型分析 characteristics 它通过高灵敏度、高自动化的微量量热仪连续、准确地监测和记录一个变化过程的量热曲线，原位、在线和无损伤地同时提供热力学和动力学信息，它已经成为鉴定生物分子间相互作用的首选方法。 可获得生物分子相互作用的完整热力学参数，包括结合常数（Ka）、结合位点数（n）、摩尔结合焓（△H）、摩尔结合熵（△S）、摩尔恒压热容（△Cp），和动力学参数(如酶促反应的Km和kcat）,用来表征生物分子间的相互作用。 独特特点： 样品用量小，方法灵敏度和精确度高(仪器最小可检测热功率2 nW，最小可检测热效应0.125uJ，生物样品最小用量0.4ug，温度范围2 ℃ - 80 ℃，滴定池体积(1.43 ml)。 实验时间较短(典型的ITC实验只需30-60分钟，并加上几分钟的响应时间)， 操作简单(整个实验由计算机控制，使用者只需输入实验的参数，如温度、注射次数、注射量等，计算机就可以完成整个实验，再由Origin软件分析ITC得到的数据)。 测量时不需要制成透明清澈的溶液, 而且量热实验完毕的样品未遭破坏，还可以进行后续生化分