Hyaluronan (HA) has been regioselectively oxidized so to transform nearly quantitatively the primary alcoholic functions of D-N-acetylglucosamine residues in carboxylate groups. The resulting product (HAOX) has been characterized by means of H-1 NMR, viscosity, and spectroscopic measurements in aqueous media. A comparative analysis of Zn(II) uptake and of methylene blue binding by HA and HAOX in aqueous solution has been also carried out (FTIR, UV absorption, and CD experiments). HAOX exhibits polyelectrolytic features traceable to a doubling of chains charge density with respect to native HA and to the disruption of the intrachain hydrogen bonds prevailing in the latter.