arylsulfatase G; ASG (ARSG, KIAA1001, UNQ839/PRO1777)

Function

• displays arylsulfatase activity at acidic pH with pseudosubstrates, such as p-nitrocatechol sulfate & also, but with lower activity, p-nitrophenyl sulfate & 4-methylumbelliferyl sulfate
• oxidation of Cys to 3-oxoalanine seems essential for catalytic activity

Kinetic parameters:

• KM=4.2 mM for p-nitrocatechol sulfate
• Vmax=63.5 umol/min/mg enzyme toward p-nitrocatechol sulfate
• pH dependence: optimum pH is 5.4
• temperature dependence: most efficient at 45-50 degrees C

Inhibition:

• inhibited by phosphate
• the phosphate forms a covalent bond with the active site 3-oxoalanine

Cofactor: binds 1 Ca+2 per subunit (putative)

Structure

• N-glycosylated
• belongs to the sulfatase family

Compartment

lysosome

Expression

• widely expressed
• very low expression in brain, lung, heart & skeletal muscle

Notes

• previously observed endoplasmic reticulum localization is most likely due to folding/maturation problems for overexpressed proteins

More general terms

• arylsulfatase
• Ca+2 binding protein
• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=22901
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:22901
• OMIM: https://mirror.omim.org/entry/610008
• UniProt: http://www.uniprot.org/uniprot/Q96EG1.html