Document Detail


Spectrophotometric determination of protein concentration.
MedLine Citation:
PMID:  18429266     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The concentration of a purified protein in solution is most conveniently and accurately measured using absorbance spectroscopy. The absorbance, A, is a linear function of the molar concentration, C, according to the Beer-Lambert law: A = epsilon x l x c, where e is the molar absorption coefficient and l is the cell path length. This unit provides protocols for calculation of epsilon for a folded or unfolded protein, making use of the average epsilon values for the three contributing chromophores in proteins (the side chains of Trp, Tyr, and Cys). A basic protocol describes how to measure the concentration of a protein using the calculated epsilon and the Beer-Lambert law. A sensitive method is provided for measuring the concentration of proteins that contain few if any tryptophan or tyrosine residues, and a simple method is provided for estimating total protein concentration in crude extracts.
Authors:
Gerald R Grimsley; C Nick Pace
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Current protocols in protein science / editorial board, John E. Coligan ... [et al.]     Volume:  Chapter 3     ISSN:  1934-3663     ISO Abbreviation:  -     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2008-04-22     Completed Date:  2008-08-08     Revised Date:  2008-12-15    
Medline Journal Info:
Nlm Unique ID:  101287868     Medline TA:  Curr Protoc Protein Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  Unit 3.1     Citation Subset:  IM    
Affiliation:
The Texas A&M University System Health Science Center, College Station, Texas, USA.
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MeSH Terms
Descriptor/Qualifier:
Protein Folding
Proteins / analysis*
Spectrophotometry, Ultraviolet / methods*
Chemical
Reg. No./Substance:
0/Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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