The present invention provides, among other things, methods for the characterization of recombinant Heparan NSulfatase(HNS) during manufacture. The present invention uses capillary zone electrophoresis to determine the charge profile, isoform distribution, and/or glycan profile of recombinant HNS and represents a quality feature for the batch consistency, storge stability, biological half- life, pharmacokinetic, pharmacodynamic and biological activity of the enzyme. In particular, such characterization methods may be beneficial to optimize conditions and ensure consistency for the manufacture of HNS for the treatment of a patient diagnosed with Sanfilippo syndrome using enzyme replacement therapy.
