This is a family of Glucuronate isomerases also known as D-glucuronate isomerase, uronic isomerase, uronate isomerase, or uronic acid isomerase, EC:5.3.1.12. This enzyme catalyses the reactions: D-glucuronate <=> D-fructuronate and D-galacturonate <=> D-tagaturonate. It is not however clear where the experimental evidence for this functional assignment came from and thus this family has no literature reference.