Sulfatase

Sulfatases are enzymes of the esterase class that catalyze the hydrolysis of sulfate esters. These may be found on a range of substrates, including steroids, carbohydrates and proteins. Sulfate esters may be formed from various alcohols and amines. In the latter case the resultant N-sulfates can also be termed sulfamates.

Sulfatases play important roles in the cycling of sulfur in the environment, in the degradation of sulfated glycosaminoglycans and glycolipids in the lysosome, and in remodelling sulfated glycosaminoglycans in the extracellular space. Together with sulfotransferases, sulfatases form the major catalytic machinery for the synthesis and breakage of sulfate esters.

Occurrence and importance
Sulfatases are found in lower and higher organisms. In higher organisms they are found in intracellular and extracellular spaces. A large number of sulfatases are localized in the lysosome, an acidic digestive organelle found within the cell. Lysosomal sulfatases cleave a range of sulfated carbohydrates including sulfated glycosaminoglycans and glycolipids. Genetic defects in sulfatase activity can arise through mutations in individual sulfatases and result in certain lysosomal storage disorders with a spectrum of phenotypes ranging from defects in physical and intellectual development.

Three-dimensional structure
The following sulfatases have been shown to be structurally related based on their sequence homology:
 * cerebroside-sulfatase
 * steryl-sulfatase
 * arylsulfatase A (ASA), a lysosomal enzyme which hydrolyzes cerebroside sulfate;
 * arylsulfatase B (ASB) which hydrolyzes the sulfate ester group from N-acetylgalactosamine 4-sulfate residues of dermatan sulfate;
 * arylsulfatase C (ASD) and E (ASE); steryl-sulfatase (STS), a membrane bound enzyme which hydrolyzes 3-beta-hydroxy steroid sulfates;
 * iduronate 2-sulfatase (IDS), a lysosomal enzyme that hydrolyzes the 2-sulfate groups from iduronic acids in dermatan sulfate and heparan sulfate;
 * N-acetylgalactosamine-6-sulfatase, which hydrolyzes the 6-sulfate groups of the N-acetyl-D-galactosamine of chondroitin sulfate and D-galactose 6-sulfate units of keratan sulfate;
 * N-sulfoglucosamine sulfohydrolase, the lysosomal enzyme that hydrolyses N-sulfo-D-glucosamine into glucosamine and sulfate;
 * glucosamine-6-sulfatase (G6S), which hydrolyzes the N-acetyl-D-glucosamine 6-sulfate units of heparan sulfate and keratan sulfate;
 * N-sulfoglucosamine sulfohydrolase, the lysosomal enzyme that hydrolyses N-sulfo-D-glucosamine into glucosamine and sulfate;
 * sea urchin embryo arylsulfatase ;
 * green algae arylsulfatase, which plays a role in the mineralization of sulfates; and
 * arylsulfatase from Escherichia coli, Klebsiella aerogenes and Pseudomonas aeruginosa.

Human proteins containing this domain
ARSA;     ARSB;      ARSD;      ARSE;      ARSF;      ARSG;      ARSH;      ARSI; ARSJ;     ARSK;      GALNS;     GNS;       IDS;       PIGG;      SGSH;      STS; SULF1;    SULF2;