Estimating and Partitioning the Flux of ATP in Cells in Culture using mol cell -1 s -1 and the Stoichiometries of Metabolism

Abstract

We have demonstrated the advantages of using moles of a substance per cell as a metric for dose/exposure in cell culture. This dosing metric greatly increases the information content of data and enhances the repeatability and quality of experimental results compared to traditional dosing metrics, such as initial extracellular concentration. However, the use mol cell-1 or mol cell-1 s-1 for cell culture work can be applied beyond the expression of dose of a xenobiotic. We have applied the use of mol cell-1 s-1 to generate new knowledge on the flux of ATP in cells. Using data generated on the rates of oxygen consumption (OCR), proton efflux rate (PER) and proton production rate (PPR) by cells, as quantitated by extracellular flux analyzers (e.g. Agilent/Seahorse Bioscience instrumentation), the flux of ATP can be estimated. The use of moles as a base unit meshes directly with the chemistry and biochemistry of the system; allows stoichiometric relationships to be revealed; and provides a universal approach for direct comparison of experimental results from different cells. This work is an advance our 2015 presentation as several unknown unknowns were identified. Examples of each of these will be presented demonstrating how using the units of mol cell-1 s-1 leads to: data that have greater information content; absolute results that can be compared directly between laboratories around the world; and advancements pushing the frontiers of Quantitative Redox Biology.