Answer:
Positively charged: Lysine, Histidine
Negatively charged: Asparagine, Phenylalanine, Glutamatic acid, Alanine, Glycine, Leucine, Aspartic acid
Explanation:
The charge of an amino acid in solution is determined by its isoelectric point, pI, which is the characteristic pH in which the net electric charge of the amino acid is zero. In solutions of pH below the isoelectric point, the amino acid has a net positive charge whereas in solutions with pH above isoelectric point, the net charge on the amino acid is negative.
In a buffer solution of pH 6.5, the following charges are present in the amino acids given:
<em>Positively charged: Lysine (pI = 9.74), Histidine (pI = 7.59)</em>
<em>Negatively charged: Asparagine (pI = 5.07), Phenylalanine (pI = 5.48), Glutamatic acid (pI = 3.22), Alanine (pI = 6.01), Glycine (pI = 5.97), Leucine (pI = 5.98), Aspartic acid (pI = 2.77)</em>
