Nomenclature and guideline to express the amount of a membrane protein synthesized in animal cells in view of bioprocess optimization and production monitoring

Studies of a bioprocess optimization and monitoring for protein synthesis in animal cells face a challenge on how to express in quantitative terms the system performance. It is possible to have a panel of calculated variables that fits more or less appropriately the intended goal. Each mathematical expression approach translates different quantitative aspects. We can basically separate them into two categories: those used for the evaluation of cell physiology in terms of product synthesis, which can be for bioprocess improvement or optimization, and those used for production unit sizing and for bioprocess operation. With these perspectives and based on our own data of kinetic S2 cells growth and metabolism, as well as on their synthesis of the transmembrane recombinant rabies virus glycoprotein, here indicated as P, we show and discuss the main characteristics of calculated variables and their recommended use. Mainly applied to a bioprocess improvement/optimization and that mainly used for operation definition and to design the production unit, we expect these definitions/recommendations would improve the quality of data produced in this field and lead to more standardized procedures. In turn, it would allow a better and easier comprehension of scientific and technological communications for specialized readers.