Galsufase is a variant form of the polymorphic human enzyme N-acetylgalactosamine 4-sulfatase of recombinant DNA origin. Galsulfase is a glycoprotein with a molecular weight of approximately 56 kD. The recombinant protein is comprised of 495 amino acids and contains six asparagine-linked glycosylation sites, four of which carry a bis mannose-6-phosphate manose7 oligosaccharide for specific cellular recognition. Post-translational modification of Cys53 produces the catalytic amino acid residue Ca-formylglycine, which is required for enzyme activity and is conserved in all members of the sulfatase enzyme family.