May be involved in the desulfation of sulfated glycosaminoglycans in the biosynthetic pathway and may play a role as an extracellular regulator of proteoglycan mediated signaling. Binds 1 Ca(2+) ion per subunit. Also localized on the cell surface. Strongly expressed in the floor plate, choroid plexus and cartilage. Weaker expression seen in the eye, lung brain, spinal cord, urinary bladder, testis, ovary and uterus. Abundantly and specifically expressed in the floor plate region of the spinal cord at embryonic day 13 (E13) and E15 and at lower levels at postnatal day 1 (P1). A high level expression was also observed in the ventral hindbrain and midbrain. No expression was seen in the notochord at these stages. Prominent expression in the nervous system was also seen in the choroid plexus. At E13, expression was also seen in the dorsomedial forebrain and roof of the hind brain. Robust and specific expression was detected in the choroid plexus epithelium of the lateral, 3rd and 4th ventricles at E15 and P1 and persisted into adulthood. In the CNS, expression was detected in thalamic and hypothalamic regions at E13, E15 and P1. In embryos, it was highly expressed in the limb buds, face region, large blood vessels, olfactory pits and pleural epithelium. In particular, expression was robust and specific in bone-forming regions of the face and in the mesenchymal cells surrounding the developing cartilages of the extremities. 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. Belongs to the sulfatase family.