Heparosan-N-sulfate-glucuronate 5-epimerase (, heparosan epimerase, heparosan-N-sulfate-D-glucuronosyl 5-epimerase, C-5 uronosyl epimerase, polyglucuronate epimerase, D-glucuronyl C-5 epimerase, poly[(1,4)-beta-D-glucuronosyl-(1,4)-N-sulfo-alpha-D-glucosaminyl] glucurono-5-epimerase) is an enzyme with system name poly((1->4)-beta-D-glucuronosyl-(1->4)-N-sulfo-alpha-D-glucosaminyl) glucurono-5-epimerase. This enzyme catalyses the following chemical reaction