Glucosamine-N-Acetyl-6-Sulfatase (GNS)

GNS is a lysosomal enzyme found in all cells. It is involved in the catabolism of heparin, heparan sulphate, and keratan sulphate. Deficiency of this enzyme results in the accumulation of undegraded substrate and the lysosomal storage disorder mucopolysaccharidosis type IIID (Sanfilippo D syndrome). Mucopolysaccharidosis type IIID is the least common of the four subtypes of Sanfilippo syndrome. the N-terminal amino acid sequence of the 78-kD form A species and the 32-kD form B species are identical, indicating that the 78-kD form A polypeptide is processed by internal peptidase cleavage to a 32-kD N-terminal species and a 48-kD C-terminal species. Full-length G6S contains several N-glycosylation sites and a hydrophilic region, rich in basic amino acids, that may represent the proteolytic cleavage site.