Zwitterion Amino acid exists as a dipolar ion. .-COOH loses H+,-NH2 gains H+. H,N一CH一C-OH HN-CH-C- R R uncharged structure dipolar ion,or zwitterion (minor component) (major component) Copyright2005 Pearson Prentice Hall,Inc. Actual structure depends on pH. Chapter 24 =>10 Chapter 24 10 Zwitterion • Amino acid exists as a dipolar ion. • -COOH loses H+ , -NH2 gains H+ . • Actual structure depends on pH. =>