PHOSPHATE ACTIVITY IN BIOLOGICAL FLUIDS

首席研究员最近开发了一种新的离子选择性电极 (ISE)其响应于二元磷酸盐的活性。 磷酸盐- 伊势已被证明对磷酸根离子具有良好的选择性， 生物学上重要的阴离子，如氯离子、乳酸根和乙酸根。 的 主要研究者现在建议使用这种磷酸酶-ISE来研究 磷酸盐结合，矿物质饱和度，以及磷酸盐物种在 唾液和牙菌斑液。 为了实现这些目标，磷酸盐- 伊势将用于以下研究：（1）直接测定 与生物学相关的磷酸根离子对的结合常数 在定义明确的化学系统中的阳离子。 测定的结合常数 通过直接测量磷酸盐活性， 验证并可能提高已公布的结合常数的准确性; (2)直接测定人唾液中磷酸盐的活性 和牙菌斑液。 磷酸盐、Ca ~（2+）、Mg ~（2+）、Ca ~ H+和F-同时测定的伊势方法在这些生理 液体将用于计算离子活度积（IAP）， （3）开发一种微米级磷酸盐-ISE， 测量微量样品中的磷酸盐活性。 龋齿是一个网站- 该部位的斑块数量较少的特定疾病。 一 微米大小的磷酸盐-ISE版本将被开发，以协助 这些单点样品分析;（40测定磷酸盐-ISE 阴离子的选择性系数，对于生理 实验或生化系统。 ISE经常受到干扰 这限制了电极的实用性。 生理缓冲液如HEPES。CAPS等，和生物阴离子 如脂肪酸、有机酸等，将是成功的关键 磷酸盐-ISEf或生物化学分析的应用;和（5）研究 磷酸盐-ISE对磷酸根离子的选择性高于其他离子的机制 离子，结合计算机建模和NMR。 结果是 机理研究可能导致改进的磷酸盐-ISE。

The principal investigator recently developed a new ion-selective electrode (ISE) which responds to the activity of dibasic phosphate. This phosphate- ISE has been shown to have good selectivity for phosphate ions over biologically important anions such as chloride, lactate and acetate. The principal investigator now proposes to use this phosphatase-ISE to study phosphate binding, mineral saturation, and the role of phosphatespecies in saliva and dental plaque fluid. To accomplish these goals, the phosphate- ISE will be employed for the following studies; (1) directly determine binding constants for phosphate ion pairs with biologically relevant cations in well-defined chemical systems. Binding constatns determined through the direct measurement of phosphate activities will be used to verify and possibly improve the accuracy of published binding constants; (2) directly determine the activity of phosphate species in human saliva and dental plaque fluid. The activities of phosphate species, Ca2+, Mg2+, H+, and F- determined simultaneously by ISE methods in these physiological fluids will be used to calculate ionic activity products (IAP) with respect to various salts; (3) develop a micron-sized phosphate-ISE for the measurement of phosphate activities in micro-samples. Caries is a site- specific disease where the amount of plaque at that site is small. A micron-sized version of the phosphate-ISE will be developed to assist in the analysis of these single-site samples; (40 determine phosphate-ISE selectivity coefficients for anions that are important for physiological experiments or biochemical systems. ISEs often suffer from interferences that limit the utility of the electrode.Selectivity coefficients for physiological buffers such as HEPES. CAPS, etc., and biological anions such as fatty acids, organic acids, etc., will be essential for the successful application of the phosphate-ISEf or biochemical analysis; and (5) study the mechanism for phosphate-ISE selectivity to phosphate- ions over other ions, in conjunction with computer modeling and NMR. The results from this mechanism study may lead to an improved phosphate-ISE.