PHOSPHATE ANALOG PROBES OF RED CELL METABOLISM

磷酸盐类似物是化学上与正磷酸盐相关的化合物，但 有一个或两个氧原子的化学取代。 这些 取代导致原子结构的独特变化， 可滴定质子的酸度，以及核磁共振（NMR） 每种化合物的光谱。 这些独特的特性将被利用 用核磁共振波谱法研究人红细胞的两个区域 生理学：膜阴离子转运和能量代谢。 阴离子 将通过同时观察细胞内和 细胞外共振，或者是由于pH值而自然发生的， 敏感的化学位移，或通过添加 细胞外顺磁位移试剂。 快速的膜转运 交换化合物将通过饱和转移方法来研究。 将研究转运机制的浓度和pH依赖性， 和净阴离子电导将使用离子载体和抑制剂测量 阴离子转运蛋白。 这些运输特点将是 与用于阴离子运输的可滴定电荷模型相比。 由于这些 化合物与正磷酸盐具有化学相似性，它们对 将通过监测葡萄糖来研究红细胞能量代谢 利用，乳酸生产，细胞内pH值，和有机合成 磷酸盐（2，3-DPG和ATP）。 磷酸盐类似物对核苷的影响 （肌苷）能量代谢也将被阐明。 此外该 类似物对磷酸果糖激酶活性的影响（主要 糖酵解控制酶（由正磷酸盐刺激）和甘油醛 磷酸脱氢酶（唯一结合磷酸的糖酵解酶 从头转化为代谢中间体）进行研究。 代谢期间 磷酸盐酶解的研究证据将被寻找 类似物，从F-和 正磷酸盐，并用于磷酸盐类似物的酶促掺入 糖酵解代谢物

Phosphate analogues are compounds chemically related to orthophosphate, but having chemical substitutions for one or two oxygen atoms. These substitutions result in unique changes in atomic structure, the number and acidity of titratible protons, and in the nuclear magnetic resonance (NMR) spectrum of each compound. These unique characteristics will be exploited to study by means of NMR spectroscopy two areas of human erythrocyte physiology: membrane anion transport and energy metabolism. Anion transport will be studied by simultaneous observation of intracellular and extracellular resonances, either naturally occurring as a result of pH sensitive chemical shifts, or induced by means of addition of an extracellular paramagnetic shift reagent. Membrane transport of rapidly exchanging compounds will be studied by saturation-transfer methods. Concentration and pH dependence of the transport mechanism will be studied, and net anion conductance will be measured using ionophores and inhibitors of the anion transport protein. These transport characteristics will be compared to the titratible charge model for anion transport. Since these compounds bear chemical similarities to orthophosphate, their effects on red cell energy metabolism will be studied, by monitoring glucose utilization, lactate production, intracellular pH, and synthesis of organic phosphates (2,3-DPG and ATP). Phosphate analogue effects on nucleoside (inosine) energy metabolism will also be elucidated. In addition, the influence of analogues on the activity of phosphofructokinase (a major glycolysis control enzyme stimulated by orthophosphate) and glyceraldehyde phosphate dehydrogenase (the only glycolytic enzyme incorporating phosphate de novo into metabolic intermediates) will be studied. During metabolic studies evidence wil be sought for enzymatic hydrolysis of phosphate analogues, intracellular synthesis of fluorophosphate from F- and orthophosphate, and for enzymatic incorporation of phosphate analogues into glycolytic metabolites.