Cellular metabolism refers to the orchestration of the chemical and enzymatic reactions that constitute the life process of a cell. These reactions include a vast number of different chemical and enzymatic reactions, relating to the growth and maintenance of the cell. A cell carries out a variety of functions, such as DNA replication, DNA transcription, RNA translation, digestion of macromolecules, construction of macromolecules, and monitoring of the extracellular and intracellular conditions. These chemical and enzymatic reactions occur simultaneously within an active cell. Moreover, these reactions do not take place in isolation; rather the pace of each reaction is regulated, in turn, by the product of one or more other reactions. Overall, the organization of cellular metabolism is embedded in a vast network of inter-related cellular reactions. Given this interdependency, it is apparent that analytes that affect one or more aspects of cellular metabolism are likely to manifest their impact on characteristics of the cell, including pH of intracellular compartments. The pH within various cellular compartments is regulated to provide for the optimal activity of many cellular processes. For example, in the secretory pathway, post-translational processing of secretory proteins, the cleavage of prohormones, and the retrieval of escaped luminal endoplasmic reticulum proteins are all pH-dependent.