23. How Much Alanine Is Present as the Completely Uncharged Species? At a pH equal to the isoelectric point on alanine, the net charge on alanine is zero. Two structures can be drawn that have a net charge of zero, but the predominant form of alanine at its pl is zwitterionic. CH3 H₂N-C-C CH3 H₂N-C- 0 H Zwitterionic H OH Uncharged (a) Why is alanine predominantly zwitterionic rather than completely uncharged at its pl? (b) What fraction of alanine is in the completely uncharged form at its pl? Justify your assumptions.