Hydrolyzes cerebroside sulfate. H2O + N-acyl-1-beta-D-(3-O-sulfo)-galactosyl-sphing-4-enine = a beta-D-galactosyl-(1<->1')-N-acylsphing-4-enine + H(+) + sulfate Binds 1 Ca(2+) ion per subunit. Inhibited by phosphate. The phosphate forms a covalent bond with the active site 3-oxoalanine. kcat is 0,087 sec(-1) with galactosyl-3-sulfate ceramide as substrate. Optimum pH is 4.5. Homodimer at neutral pH and homooctamer at acidic pH. Exists both as a single chain of 58 kDa (component A) or as a chain of 50 kDa (component B) linked by disulfide bond(s) to a 7 kDa chain (component C). Interacts with SUMF1. The conversion to 3-oxoalanine (also known as C-formylglycine, FGly), of a serine or cysteine residue in prokaryotes and of a cysteine residue in eukaryotes, is critical for catalytic activity. This post-translational modification is severely defective in multiple sulfatase deficiency (MSD). The disease is caused by variants affecting the gene represented in this entry. The protein represented in this entry is involved in disease pathogenesis. Arylsulfatase A activity is impaired in multiple sulfatase deficiency due to mutations in SUMF1 (PubMed:15146462). SUMF1 mutations result in defective post-translational modification of ARSA at residue Cys-69 that is not converted to 3-oxoalanine (PubMed:7628016). The metal cofactor was first identified as magnesium ion, based on the structure of the recombinant protein, but when purified from human placenta, the protein contains 1 calcium ion per subunit. Belongs to the sulfatase family. Arylsulfatase A entry Leiden Open Variation Database (LOVD)