UDP-glucuronic acid dehydrogenase (UDP-4-keto-hexauronic acid decarboxylating) (, UDP-GlcUA decarboxylase, ArnADH) is an enzyme with systematic name UDP-glucuronate:NAD<sup>+</sup> oxidoreductase (decarboxylating). This enzyme catalyses the following chemical reaction
The activity is part of a bifunctional enzyme also performing the reaction of EC 2.1.2.13 (UDP-4-amino-4-deoxy-L-arabinose formyltransferase).