Say you were to do a comparison of two different amino acids to determine whether they could serve as an effective buffer in the lab. You take a solution of histidine and a solution of threonine and do a complete titration starting at pH = 1 and ending at pH = 14.
Structures for both amino acids are shown below in their neutral form. The pKa for the side chain of histidine is about 6.
Think about what the titration curves for each of these amino acids, and answer the following question.
How many buffering regions will be revealed by the titration curves for each of the amino acids?