2-[3-carboxylato-3-(dimethylammonio)propyl]-L-histidine residue
2-[3-carboxylato-3-(dimethylammonio)propyl]-l-histidine residue
A zwitterionic group obtained by transfer of a proton from the amino to the carboxy group of 2-[3-carboxy-3-(dimethylamino)propyl]-<small>L</small>-histidine residue.