E. Sievi et al., Glycan engineering of proteins with whole living yeast cells expressing rat liver alpha 2,3-sialytransferase in the porous cell wall, FEBS LETTER, 441(2), 1998, pp. 177-180
The N-glycans of recombinant proteins produced via the secretory pathway of
cultured mammalian cells are often undersialylated, and insect cells lack
sialytransferases. Undersialylated glycoproteins are rapidly cleared from t
he circulation, compromising the effect of pharmaceuticals. We show that in
cubation with living Saccharomyces cerevisiae cells expressing the catalyti
c ectodomain of rat liver alpha 2,3-sialyltransferase (ST3N(e)) in the poro
us cell wall resulted in sialylation of glycoproteins. The K-m values of th
e yeast enzyme for several substrates were similar to those of recombinant
ST3N(e) from insect cells and of authentic ST3N, The yeast strain provides
an inexpensive self-perpetuating source of ST3N activity for glycan enginee
ring of recombinant proteins. (C) 1998 Federation of European Biochemical S
ocieties.