This family of sequences from archaea and metazoans includes N-acylneuraminate-9-phosphatase Nanp from metazoa []and glyceraldehyde 3-phosphate phosphatases from archaea []. Pyrococcus species appear to have three different forms of this enzyme, so it is unclear whether all members of this family have the same function. This family is a member of the haloacid dehalogenase (HAD) superfamily of hydrolases which are characterised by three conserved sequence motifs. By virtue of an alpha helical domain in-between the first and second conserved motif, this family is a member of subfamily IA [].
