Why the pH does affect the separation of amino acids by electrophoresis?

Answer 1

pH affects the separation of amino acids or protein in electrophoresis, because this method requires that the molecules carry a certain charge. The proteins will move towards the anode if negatively charged or towards the cathode if positively charged.

The pI (isoelectric point) of an amino acid or of a protein determines whether the certain amino acid/protein will be ionized and charged at a certain pH. It is defined as the pH at which a particular molecule or surface carries no net charge. Therefore, the pH determines whether the protein will be positively charged (if the pH<pI) or negatively charged (pH>pI).

Answer 2

The separation of amino acids by electrophoresis is influenced by the pH because it affects the ionization state of the amino acids. At different pH levels, amino acids can exist in different forms (protonated or deprotonated), which affects their charge. Amino acids with different charges will migrate at different speeds during electrophoresis, leading to their separation.