Remember, every single amino acid contains an a terminal alpha carboxyl group and a terminal alpha amino group. And those two groups are also capable of losing and gaining h atoms at specific PH values. So if the side chain is non ionizable, then the isoelectric point of that amino acid is the average of the PKA values of the terminal alpha amino group and the terminal alpha carboxyl group. So one example of a nonionisable amino acid is glycine. Another example is valine. We have Alanine leucine, isolucine and so forth.