World Journal of Chemical Education
ISSN (Print): 2375-1665 ISSN (Online): 2375-1657 Website: http://www.sciepub.com/journal/wjce Editor-in-chief: Prof. V. Jagannadham
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World Journal of Chemical Education. 2014, 2(4), 59-61
DOI: 10.12691/wjce-2-4-3
Open AccessArticle

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

Cassidy M. Dobson1 and Nathan S. Winter1,

1Department of Chemistry and Biochemistry, St. Cloud State University, St. Cloud, Minnesota, United States

Pub. Date: December 25, 2014

Cite this paper:
Cassidy M. Dobson and Nathan S. Winter. The Identification of Amino Acids by Interpretation of Titration Curves: An Undergraduate Experiment for Biochemistry. World Journal of Chemical Education. 2014; 2(4):59-61. doi: 10.12691/wjce-2-4-3

Abstract

Undergraduate biochemistry students should have great familiarity with titration curves. These curves allow the prediction of protonation states, charges, and isoelectric points. Here we describe an experiment in which students identify four amino acids based on their titration behavior. Students make solutions of each unknown amino acid and monitor the change in pH upon adding aliquots of a strong base. They identify the amino acids based on the shapes of the curves. They annotate the plots with isoelectric points, pKas, buffering regions and the structures of the amino acids.

Keywords:
titration curve amino acids pH biochemistry pKa isoelectric point

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References:

[1]  Barnum, D., (1999). Predicting Acid-Base Titration Curves without Calculations. Journal of Chemical Education 76(7): 938-942.
 
[2]  Bodner, G. (1986). Assigning the pKa’s of Polyprotic Acids. Journal of Chemical Education 63(3): 246-247.
 
[3]  Heimer, E. (1972). Quick Paper Chromatography of Amino Acids. Journal of Chemical Education 49(8): 1.
 
[4]  Herman, D., Booth, K., et al. (1990). The pH of Any Mixture of Monoprotic Acids and Bases. Journal of Chemical Education 67(6): 501-502.
 
[5]  Kuehl, L. (1978). A Novel Method for Presenting the Amino Acids in an Introductory Biochemistry Course. Journal of Chemical Education 55(11): 3.
 
[6]  Kraft, A. (2003). The Determination of the pKa of Multiprotic, Weak Acids by Analyzing Potentiometri Acid-Base Titration Data with Difference Plots. Journal of Chemical Education 80(5): 554-559.
 
[7]  Meister, A. (1965). Biochemistry of the Amino Acids. New York, Academic Press Inc.
 
[8]  Sae, S. W. and B. A. Cunningham (1971). Chromatographic separation and identification of amino acids. Journal of Chemical Education 48(4): 275.
 
[9]  Weiss, H. (2007). The Roles of Acids and Bases in Enzyme Catalysis. Journal of Chemical Education 84(3): 440-442.