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ERIC Number: EJ913312
Record Type: Journal
Publication Date: 2010-Mar
Pages: 4
Abstractor: As Provided
ISSN: ISSN-0021-9584
Thermodynamic Exploration of Eosin-Lysozyme Binding: A Physical Chemistry and Biochemistry Laboratory Experiment
Huisman, Andrew J.; Hartsell, Lydia R.; Krueger, Brent P.; Pikaart, Michael J.
Journal of Chemical Education, v87 n3 p299-302 Mar 2010
We developed a modular pair of experiments for use in the undergraduate physical chemistry and biochemistry laboratories. Both experiments examine the thermodynamics of the binding of a small molecule, eosin Y, to the protein lysozyme. The assay for binding is the quenching of lysozyme fluorescence by eosin through resonant energy transfer. In both experiments, students measure fluorescence quenching at constant lysozyme concentration as a function of added eosin and determine the dissociation constant, K[subscript D], and [Delta]G[degree] for binding. In the physical chemistry experiment, students repeat the fluorescence measurements at several temperatures to determine the temperature dependence of [Delta]G[degree], and therefore [Delta]H[degree] and [Delta]S[degree] as well. Typical student results yield a K[subscript D] of (28.3 [plus or minus] 7.5) [mu]mol L[superscript -1] and a binding [Delta]G[degree] of (-26.04 [plus or minus] 0.70) kJ mol[superscript -1] at 25 [degree]C. [Delta]H[degree] and [Delta]S[degree] of binding are found to be (-4.1 [plus or minus] 2.5) kJ mol[superscript -1] and (73.9 [plus or minus] 8.7) J mol[superscript -1] K[superscript -1], respectively. This pair of laboratories represents an interdisciplinary module in which students in different courses examine the same system but from different perspectives and with different emphases. (Contains 3 figures and 1 table.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Evaluative
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A