Journal of Knowledge & Health1735-577X10320150627Glycosylation Engineering of Human Recombinant Proteins in New S2 System445110.1234/knh.v10i3.714FAJafarVatandoost. j.vatan@hsu.ac.irLeilaKhalili201410272014122720141220Insect expression systems have been used to achieve high expression of recombinant and complex proteins, but disability of insects in the synthesis of N-Glycan products similar to mammals has been a controversial conflict debate in recent years. Glycosylation products in insects contain high or low end of mannose units. The main reason for this inability is the low level of activity of a number of enzymes including β-N - (1 and 2) acetyl glucosamine transferase I and II, β- (1 and 4) galactosyl transferase, α-(2, 3) and α-(2, 6) sialyl transferase. In addittion, a hexoaminidase that remove N-acetyl glucosamine at the end of glycan products and prevents binding of galactose and Sialic acid to glycan products have been discovered in insects. So the insect cells can be engineered to produce glycan products similar with mammalians and remove blocking agents of synthesis of sialyl and galactose products. In this systematic review, the glycosylation pathways in mammals and insects and engineering of possible glycosylation pathways in S2 cells have been investigated.