What is the isoelectric point of serine (pK_a of α-CO₂H, 2.21; pK_a of α-NH₂, 9.15)?

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Quizplus · Accepted Answer

The isoelectric point (pI) of an amino acid is the pH at which the molecule carries no net electric charge. For amino acids with non-ionizable side chains, like serine, the pI can be calculated as the average of the pKa values of the two ionizable groups, which are the carboxyl group (pKa1 = 2.21) and the amino group (pKa2 = 9.15). Thus, pI = (2.21 + 9.15) / 2 = 5.68.

What Is the Isoelectric Point of Serine (PKa of α-CO2H

What Is the Isoelectric Point of Serine (PK_a of α-CO₂H