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.

直接确定H+/0化学计量比的新系统 呼吸脉冲的快速启动（在实验室中开发） 用于与两个系统的广泛研究。 琥珀酸酯作为电子 完整线粒体激活能量转导位点II和 iii。 细胞色素C和线粒体分离的位点III降低。 在这两种情况下 观察到了一种新现象 - H+/0的快速爆发在 50毫秒，耗散300毫秒。 当忽略0到0.8 s的数据时 在LST假设上，其余数据将其推回到零时间 订购动力学，我们确认Lehninger的零时间值为8 琥珀酸酯系统而不是维克斯特罗姆（Wikstrom）青睐的6个 米切尔。 但是，我们对外推程序的进一步分析 导致我们得出的结论是，这种技术没有获得的价值是 可靠。 我们正在考虑一种替代模型 呼吸和质子易位除了一个直接运动 质子每电子质子，如米切尔假设中所述。 在这个 模型没有H+/0的固定比率，而是数字是一个 可变仅由呼吸解放的能量量决定 以及可以在lambdamuh+上移动的质子数量 立即存在。 工作一直在完成和测试替代方案 确定早期H+/0的实验系统。 新系统没有 使用放松时间校正电极或存在 一氧化碳气氛。