Characteristics E. coli Yeast Insect cells Mammalian cells
Cell growth rapid (30 min) rapid (90 min) slow (18-24 h) slow (24 h)
Complexity of growth medium minimum minimum complex complex
Cost of growth medium low low high high
Expression level high low - high low - high low - moderate
Extracellular expression secretion to periplasm secretion to medium secretion to medium secretion to medium
Posttranslational modifications

Protein folding refolding usually required refolding may be required proper folding proper folding
N-linked glycosylation none high mannose simple, no sialic acid complex
O-linked glycosylation no yes yes yes
Phosphorylation no yes yes yes
Acetylation no yes yes yes
Acylation no yes yes yes
gamma-Carboxylation no no no yes


Gene Expression Systems. Using nature for the art of expression (Fernandez, J.M. & Hoeffler, J.P., eds), Academic Press, San Diego, 1999.