[Advances in the production of humanized glycoprotein by different expression systems--a review]

Theraputic glycoprotein is increasingly important for human health with new developments of the recombinant DNA technology and the protein glycosylation theory. Most glycoproteins are produced in mammalian cells with high cost and low yield as the bottleneck in production. Bacterial expression systerm is important but rather diffcult by the restriction of both theory and technology. Therefore, yeast glycoprotein expression systems have been established, and they are of the utmost importance. This review summarized N-linked glycosylation processes of the different expression systems and genetic engineering of the glycosylation pathways to "humanized" glycoproteins.