Figure 2. Titration curves of the amino acids histidine, glutamine, glutamic acid and lysine. Based on the shape of the titration curves students are able to differentiate the four amino acids

From

The Identification of Amino Acids by Interpretation of Titration Curves: An Undergraduate Experiment for Biochemistry

Cassidy M. Dobson, Nathan S. Winter

World Journal of Chemical Education. 2014, 2(4), 59-61 doi:10.12691/wjce-2-4-3