This document discusses downstream processing in biopharmaceuticals. It provides examples of characterizing proteins like human serum albumin, describing its molecular weight, isoelectric point, and hydropathicity. It also discusses large scale protein production methods like transfection, purification using affinity and size exclusion chromatography, and challenges like glycosylation that can be addressed through techniques such as mutagenesis and using insect cells. The typical downstream processing flow is outlined involving clarification, filtration, chromatography, and viral clearance steps.