Measurement of Cell-Culture Glycosidase Activity

Heterogeneity of cell culture-produced glycoproteins often results from the presence or absence of a few sugars found on the terminus of glycoprotein oligosaccharides. Variability in bioprocess factors can potentially lead to variability in this oligosaccharide heterogeneity (1 ). Although stochastic events in the intracellular biosynthetic process have long been recognized as a cause of oligosaccharide heterogeneity (2 ), more recent data has demonstrated that extracellular degradation by glycosidases can also contribute to oligosaccharide heterogeneity (3 ,4 ). The purpose of this chapter is to introduce the concept and consequence of glycosidase degradation, to discuss methods for evaluating whether glycosidase degradation is significant for a particular process, and to provide some potential remedies to alleviate undesirable degradation.