<p>The Haloacid Dehydrogenase (HAD) superfamily includes phosphatases, phosphonatases, P-type ATPases, beta-phosphoglucomutases, phosphomannomutases, and dehalogenases, which are involved in a variety of cellular processes ranging from amino acid biosynthesis to detoxification [<cite idref="PUB00003337"/>]. Proteins in this entry are mostly uncharacterised, though they form a distinct subgroup within the HAD superfamily. Members are found almost exclusively in bacteria and many species contain several paralogs, for example <taxon tax_id="562">Escherichia coli</taxon> contains a total of six proteins from this entry. Sequence similarities suggest that these enzymes are phosphatases which work on phosphorylated sugars.</p><p>The YbiV (<db_xref db="SWISSPROT" dbkey="P75792"/>) protein from E. coli has been experimentally characterised [<cite idref="PUB00028115"/>]. This enzyme catalyzes the hydrolysis of sugar phosphate to sugar and inorganic phosphate. It has a wide substrate specificity, catalyzing the hydrolysis of ribose-5-phosphate and glucose-6-phosphate most efficiently, but it is not known if these are the real substrates in vivo. The protein appears to be a monomer that contains two domains, an alpha-beta hydrolase domain that forms a Rossman fold, and an alpha-beta domain. The active site is found in a negatively charged cavity found at the interface between the two domains.</p> Cof protein