The isoelectric point(pl) of an amino acid is the pH of wihc it has no net charge. The pl of an amino acid that does not have an ionizable side chain such as alanine, is midway between its two pka values.
If an amino acid has ionizable side chain. its pl is the average of the pka values of the similarly ionizing groups.
Find the pl of the following amino acids
A. `3.22`
B. 6.44
C. 7.96
D. 5.93