Mammalian Expression System

Mammalian cells, primarily Chinese hamster ovary (CHO), are often used as an expression system for synthesis of protein that needs post-translation modification, such as glycosylation.

Advantages of mammalian cells as an expression system

Capable of post-translation modification, including phosphorylation and glycosylation
Protein produced is properly folded

Disadvantages of mammalian cells as an expression system

Expensive
Poor secretion

Expression system starts with creating transfection mixture with recombined plasmid. The mixture is transfected to cells. Once the cells grow, they are collected and desired protein is purified.

Figure 1. Mammalian expression system.