Amino Acids and pH

The structure of an amino acid allows it to act as both an acid and a base. An amino acid has this ability because at a certain pH value (different for each amino acid) nearly all the amino acid molecules exist as zwitterions. If acid is added to a solution containing the zwitterion, the carboxylate group captures a hydrogen (H ) ion, and the amino acid becomes positively charged. If base is added, ion removal of the H ion from the amino group of the zwitterion produces a negatively charged amino acid. In both circumstances, the amino acid acts to maintain the pH of the system—that is, to remove the added acid (H ) or base (OH−) from solution. #aminoAcids #PH #electroproresis #proteins #Genetics