An improved purification method for the lysosomal storage disease protein β-glucuronidase produced in CHO cells

- Acid precipitation is applied to purification of lysosomal enzyme β-Glucuronidase produced by CHO cells in a bioreactor.
- Purification efficiency improved by decreasing number of steps, time and improving recovery.
- CE analysis showed decreased dimerization and similar isoelectric profile for β-Glucuronidase purified by new method.
- New purification method does not affect the mannose-6-phosphate content of β-Glucuronidase.

Human β-glucuronidase (GUS; EC 3.2.1.31) is a lysosomal enzyme that catalyzes the hydrolysis of β-d-glucuronic acid residues from the non-reducing termini of glycosaminoglycans. Impairment in GUS function leads to the metabolic disorder mucopolysaccharidosis type VII, also known as Sly syndrome. We produced GUS from a CHO cell line grown in suspension in a 15 L perfused bioreactor and developed a three step purification procedure that yields ∼99% pure enzyme with a recovery of more than 40%. The method can be completed in two days and has the potential to be integrated into a continuous manufacturing scheme.