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| Home > JCE Print > Journal of Chemical Education > Issues >
2006
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May
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In the Laboratory
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Molecular Modeling Exercises and Experiments
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(Strept)Avidin–Biotin: Two Interrelated Experiments for the Introductory Chemistry Laboratory
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David E. Hansen, Dengda Tang, Jon A. Sanborn, and Mark D. Marshall
Department of Chemistry, Amherst College, Amherst, MA 01002
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May 2006
Vol. 83 No. 5
p. 777
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| Abstract |
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A two-experiment sequence focusing on the noncovalent complex between the egg white protein avidin (or the similar protein streptavidin, which is expressed by the bacterium Streptomyces avidinii) and the essential cofactor biotin has been developed. The association equilibrium constant for the formation of the (strept)avidin–biotin complex is 1015, one of the largest ever measured for a noncovalent interaction between a protein and small molecule. In the first of the two experiments, students employ molecular modeling techniques to examine a series of noncovalent interactions, beginning with the argon dimer and culminating with (strept)avidin–biotin complex. In the second experiment, students titrate a solution of avidin with the dye 2-[(4-hydroxyphenyl)azo]benzoic acid (HABA). HABA has an absorption maximum at 348 nm, but upon binding to avidin the maximum redshifts to 500 nm, thus allowing the quantity of complex present to be determined. From these data, the equilibrium constant for the binding of HABA to avidin is calculated.
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| Supplement |
The laboratory handouts for both of the molecular modeling and avidin–HABA titration experiments, notes for the instructor, and the necessary HyperChem files are available.
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 Contents |
Folder JCE2006p0777W containing JCE2006p0777W.doc (Microsoft Word)
and a folder of HyperChem structure files |
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| More Information |
Citation |
Hansen, David E.; Tang, Dengda; Sanborn, Jon A.; Marshall, Mark D. J. Chem. Educ. 2006 83 777.
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Keywords |
Biochemistry; Bioorganic Chemistry; Computational Chemistry; Computer-Based Learning; Equilibrium; First-Year Undergraduate / General; Hands-On Learning / Manipulatives; Laboratory Instruction; Organic Chemistry; Titration / Volumetric Analysis
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History |
Created:
Last Updated: |
3/16/2006
3/31/2006
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| Home > JCE Print > Journal of Chemical Education > Issues >
2006
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May
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777
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