Metabolic control analysis of monoclonal antibody synthesis

A general route for protein synthesis in eukaryotic cells has been proposed and applied to monoclonal antibody (MAb) synthesis. It takes into account transcription of the gene, binding of ribosomes to mRNA, and polypeptide el ongation including binding to SRP (signal recognition particles) and SRP-re ceptor, competing translocation, folding and glycosylation, assembly of the heavy and light chains in a tetrameric protein and Golgi processing and se cretion. A comprehensive mode], was built on the basis of the proposed path way. The model takes into account the mechanism of each step. Metabolic con trol analysis (MCA) principles were applied to the general pathway using th e proposed model, and control coefficients were calculated. The results sho w a shared flux control (of both pathway flux and flux ratio at the branch) among different steps, i.e., transcription, folding, glycosylation, transl ocation and building blocks synthesis. The steps sharing the control depend on the concentration of building blocks, pathway flux and levels of OST (o ligosacharyl transferase), BiP (heavy chain binding protein) and PDI (prote in disulfide isomerase). Model predictions compare well with experimental d ata for MAb synthesis, explaining the control structure of the route and th e heterogeneity of the product and also addressing future targets for impro vement of the production rate of MAbs.