2-[(3S)-3-carboxylato-3-(methylammonio)propyl]-L-histidine residue
2-[(3s)-3-carboxylato-3-(methylammonio)propyl]-l-histidine residue
A zwitterionic group obtained by transfer of a proton from the amino to the carboxy group of 2-[(3<i>S</i>)-3-carboxy-3-(methylamino)propyl]-<small>L</small>-histidine residue; major species at pH 7.3.