D-glucuronyl C5-epimerase is an enzyme that in humans is encoded by the GLCE gene.

Heparan sulfate (HS) is a negatively charged cell surface polysaccharide required for the biologic activities of circulating extracellular ligands. GLCE is responsible for epimerization of D-glucuronic acid (GlcA) to L-iduronic acid (IdoA) of HS, which endows the nascent polysaccharide chain with the ability to bind growth factors and cytokines (Ghiselli and Agrawal, 2005 [PubMed 15853773]).[supplied by OMIM, Jun 2008].
Function: Converts D-glucuronic acid residues adjacent to N-sulfate sugar residues to L-iduronic acids (By similarity).