<p>This family of proteins utilise NAD as a cofactor. The proteins in this family use nucleotide-sugar substrates for a variety of chemical reactions [<cite idref="PUB00000446"/>]. It contains the NAD(P)- binding domain (<db_xref db="INTERPRO" dbkey="IPR016040"/>) which is a commonly found domain with a core Rossmann-type fold. One of the best studied of these proteins is UDP-galactose 4-epimerase which catalyses the conversion of UDP-galactose to UDP-glucose during galactose metabolism [<cite idref="PUB00025849"/>, <cite idref="PUB00024593"/>].</p>