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ERIC Number: EJ1123446
Record Type: Journal
Publication Date: 2016-Dec
Pages: 7
Abstractor: As Provided
ISSN: ISSN-0021-9584
Analyzing Exonuclease-Induced Hyperchromicity by Uv Spectroscopy: An Undergraduate Biochemistry Laboratory Experiment
Ackerman, Megan M.; Ricciardi, Christopher; Weiss, David; Chant, Alan; Kraemer-Chant, Christina M.
Journal of Chemical Education, v93 n12 p2089-2095 Dec 2016
An undergraduate biochemistry laboratory experiment is described that utilizes free online bioinformatics tools along with readily available exonucleases to study the effects of base stacking and hydrogen bonding on the UV absorbance of DNA samples. UV absorbance of double-stranded DNA at the ?[subscript max] is decreased when the DNA bases are involved in hydrogen bonding and formation of secondary structure. When an exonuclease is added to the solution containing the DNA, the strand is digested and the interactions disappear, leading to an increase in the absorbance called hyperchromicity. This experiment utilizes exonuclease digestion of DNA to show students how base interactions and secondary structure can alter the spectroscopic properties of a sample and, by extension, how apparent concentration as calculated with Beer-Lambert's law is not necessarily representative of the true concentration of DNA in solution. Teaching applications of this laboratory experiment include enzyme kinetics and activity, secondary structure of single-stranded DNA (and its parallel to RNA structure), and an introduction to bioinformatics.
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 - Research
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A