ELECTROCHEMICAL POTENTIALS OF PROTONS IN ENERGY-TRANSDUCING MEMBRANES

能量转换膜中质子的电化学势

• 批准号: 4694479
• 负责人: R W HENDLER
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/4694479
• 关键词: Escherichia coli; acidity /alkalinity; anions; bioenergetics; cations; cellular respiration; electrochemistry; electrodes; hydrogen transport; ion transport; ionophores; mathematical model; membrane permeability; membrane potentials; mitochondria; oxygen transport; potassium; radiotracer; salicylate

A new system for direct determination of H+/0 stoichiometric ratios during the rapid initiation of a respiratory pulse (developed in the laboratory) was used for extensive studies with two systems. Succinate as electron donor with intact mitochondria activated energy transduction sites II and III. Reduced cytochrome c and mitoplasts isolated site III. In both cases a new phenomenon was observed - a rapid burst in H+/0 ratio peaking within 50 ms and dissipating by 300 ms. When data from 0 to 0.8 s was ignored and the remaining data extrapolated back to zero time on the assumption of lst order kinetics, we confirmed Lehninger's zero time value of 8 for the succinate system as opposed to 6 favored by Wikstrom or 4 favored by Mitchell. However, our further analysis of the extrapolation procedure leads us to conclude that no value obtained by this technique is dependable. We are considering an alternative model for linkage between respiration and proton translocation other than the direct movement of one proton per electron as postulated in the Mitchell hypothesis. In this model there is no fixed ratio for H+/0, but rather the number would be a variable determined solely by the amount of energy liberated by respiration and the number of protons that could be moved against the LambdaMuH+ existing at the instant. Work has continued on the completion and testing of an alternative experimental system for determing early H+/0. The new system does not employ relaxation time corrections for electrodes nor the presence of a carbon monoxide atmosphere.

直接测定 H+/0 化学计量比的新系统 呼吸脉冲的快速启动（实验室开发） 用于两个系统的广泛研究。 琥珀酸作为电子 具有完整线粒体激活能量转导位点 II 和 三． 减少的细胞色素 c 和线粒体分离位点 III。 在这两种情况下 观察到一个新现象 - H+/0 比率迅速爆发，在 50 毫秒并消散 300 毫秒。 当忽略 0 到 0.8 s 的数据时 假设 lst ，剩余数据外推至零时间 阶动力学，我们确认了 Lehninger 的零时间值为 8 琥珀酸系统，而不是 Wikstrom 喜欢的 6 或 4 喜欢的 米切尔. 然而，我们对外推程序的进一步分析 使我们得出这样的结论：通过该技术获得的任何价值都不是 可靠。 我们正在考虑一种替代模型来连接 除直接运动外的呼吸和质子易位 米切尔假说中假设的每个电子质子。 在这个 模型中 H+/0 没有固定的比率，而是一个数字 仅由呼吸释放的能量决定的变量 以及可以针对 LambdaMuH+ 移动的质子数量 存在于当下。 替代方案的完成和测试工作仍在继续 用于确定早期 H+/0 的实验系统。 新系统没有 对电极采用弛豫时间校正，也不存在 一氧化碳气氛。