Glutamine is one of the 20 amino acids. Its side chain is an amide formed by replacing the side chain hydroxyl of glutamic acid with an amine functional group, making it the amide of glutamic acid. In human blood, glutamine is the most abundant free amino acid. The isoelectric point is the pH at which a particular molecule or surface carries no net electrical charge. The isoelectric point (pH) of glutamine is 5.65.