Question

What pH should be used for electroforetic separation of mixture D-His, L-Glu and L-Ser?

Answer 1

The pH for electrophoretic separation must be so chosen that the tree components are well separated. The pH of electrophoresis is related to the pI (isoelectric point) of the amino acids. The pI are 7.59 (D-His), 3.22 (L-Glu) and 5.68 (L-Ser). The ideal separation pH will be close to the pI of L-Ser, i.e, around 5 – 6. At this pH, L-Ser will remain stagnant and will not move toward either of the electrodes. L-Glu will be negatively charged and will move toward the anode (positive electrode) while D-His will be positively charged and will migrate toward the cathode (negative electrode).