Calculate the pI value for gluatamic acid. pK a1 (carboxyl group) = 2.16, pK a2 (ammonium group) = 9.96, pK a3 (R-group) = 4.30.

So here we need to determine the isoelectric point pH for glutamic acid. From the name, it's obvious that this is an acetic amino acid. And with acetic amino acids, we're going to choose the 2 lower pKa values. So pH here equals half pKa 1+pKa 2. So that's half 2.16+4.3 0. So my isoelectric point pH would be 3.23. Now here, our amino acid with all 3 groups with their h plus molecules would look like this. Acidic hydrogen. Here, for my alpha carboxyl group, the pKa is 2.16. Since the pH is greater than 2.16, we can remove this H plus. So now that oxygen is negatively charged. Here, the pH is not greater than this value and the pH will not be greater than this value either. Here would be our structure. This is what my amino acid would look like. This represents its zwitterane ion form. We have a negative charge and a positive charge, so overall the molecule is neutral. Remember, keep in mind that your isoionic and isoelectric point is usually around the same value. When we're dealing with basic amino acids, we use the 2 larger pKa values to find our isoelectric point. Then when we have an acidic amino acid, we use the 2 lower pKas to find our isoelectric point pH. Keep these in mind whenever you're faced with questions dealing with figuring out the isoelectric point or isoelectronic point or iso ionic point of these different diaprotic and polyprotic systems.