CHO Lec3.2.8.1 cells have 4 independent mutations in the N and O glycosylation pathways. When cultured with alpha-glucosidase I inhibitor N-butyl-deoxynojirimycin, glycoproteins produced in CHO Lec3.2.8.1 cells are completely susceptible to Endo H digestion. Endo H cleaves chitobiose, leaving a single N-linked N-acetylglucosamine per site which is ideal for maintenance of protein solubility and special carb-protein interactions, such as between the first N-acetyl glucosamine residue and tryp.