Document Detail

Use of a laboratory exercise on molar absorptivity to help students understand the authority of the primary literature.
MedLine Citation:
PMID:  21591161     Owner:  NLM     Status:  In-Data-Review    
To promote understanding of the authority of the primary literature in students taking our biochemistry laboratory courses, a biochemistry laboratory exercise on the determination of an acceptable molar absorptivity value of 2-nitrophenol (2-NP) was developed. This made the laboratory course much more relevant by linking to a thematic thread, β-galactosidase, that scaffolds concepts in one exercise with those in later exercises. The substrate for the continuous assay of β-galactosidase is the chromogenic 2-nitrophenyl-β-D-galactopyranoside that produces 2-NP. In an early laboratory exercise, students determine the wavelength of maximum absorption for the protonated and deprotonated form of 2-NP at various pH values and then determine the molar absorptivity of 2-NP. Students were encouraged to discuss apparent discrepancies not only in their own determinations of molar absorptivity values for 2-NP, but also in the published molar absorptivity values for 2-NP (2,150-21,300 M(-1) cm(-1) ) at almost the same pH and at 420 nm. Finally, the students were led to a publication that serves as an authentic source for molar absorptivity of 2-NP.
Madhavan Soundararajan; Cheryl P Bailey; John Markwell
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biochemistry and molecular biology education : a bimonthly publication of the International Union of Biochemistry and Molecular Biology     Volume:  36     ISSN:  1470-8175     ISO Abbreviation:  Biochem Mol Biol Educ     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2011-05-18     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100970605     Medline TA:  Biochem Mol Biol Educ     Country:  United States    
Other Details:
Languages:  eng     Pagination:  61-4     Citation Subset:  -    
Copyright Information:
Copyright © 2008 International Union of Biochemistry and Molecular Biology, Inc.
Center for Biological Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664.
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