pH Ruler Java Applet for Developing Interactive Learning Exercises on Protonation States and Titration Curves

 

Barrette-Ng, I. & E. Lohmeier-Vogel

Tested Studies in Laboratory Teaching, 2010, Volume 31

Abstract

Students in introductory biochemistry courses often struggle to understand the basic concepts underlying the titration of weak acids, especially for important biological molecules like amino acids with more than one titratable group. In the past, we have only had limited success in trying to develop interactive laboratory and tutorial exercises to help students learn these extremely important concepts. To provide students with an intuitive and flexible graphical interface for learning about protonation states and titration curves, we have written a Java applet that allows students to explore, in a self-directed and interactive manner, how variations in pH affect the protonation states of carboxylate, amino, imidazole and thiol groups in amino acids and peptides. This simple software tool provides an effective means for developing inquiry-based computer laboratory exercises to help students improve their understanding of basic concepts involving ionization states. We also envision that once these basic concepts have been mastered, students can use the same applet to develop a deeper understanding of more advanced concepts in biochemistry, including protein purification procedures like ion exchange chromatography, protein characterization techniques like isoelectric focusing, protein-ligand interactions and enzyme catalysis.

Keywords:  acid/base balance

University of Delaware (2009)