Arylsulfatase A breaks down sulfatides, namely cerebroside 3-sulfate into cerebroside and sulfate. It is a member of the sulfatase family. The arylsulfatase A was located in lysosome-like structures and transported to dense lysosomes in a mannose 6-phosphate receptor-dependent manner. Deficiency of arylsulfatase A leads to the accumulation of cerebroside sulfate, which causes a lethal progressive demyelination. Arylsulfatase A requires the posttranslational oxidation of the -CH2SH group of a conserved cysteine to an aldehyde, yielding a formylglycine to be in an active form.