 This first resolved structure indicated that the C-terminus of one of the two dimers projected into the UDP-glucuronic acid binding site of the second dimer, thus rendering the second dimer ineffective.Further studies have investigated dimerization of UGT enzyme polymorphisms and found both homodimer and heterodimer (with genetic polymorphisms of UGT2B7 or other UGT enzymes such as UGT1A1) formation are possible, with some combinations having an effect on enzyme activity.UGT2B7 is considered to be a highly polymorphic gene.