D-glucuronate = D-fructuronate aldehydo-D-galacturonate = keto-D-tagaturonate kcat is 3.8 sec(-1) with D-galacturonate as substrate. kcat is 0.35 sec(-1) with D-glucuronate as substrate. Carbohydrate metabolism; pentose and glucuronate interconversion. Homotrimer. Belongs to the metallo-dependent hydrolases superfamily. Uronate isomerase family.