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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
1982-9-24
pubmed:abstractText
The ultraviolet absorption spectrum of proteins in 6 M guanidine is approximately that of the sum of the spectra of the constituent aromatic amino acids, phenylalanine, tyrosine, and tryptophan, plus contributions from light scattering and disulfides. A multicomponent analysis of the spectrum would theoretically permit simultaneous quantitation of each aromatic amino acid in the protein. In practice, this has not been possible, because of the similarities of the spectra of the amino acids, large differences in molar absorptivity, variable absorption by the disulfides, light scattering, and wavelength shifts which occur when the amino acids are incorporated into proteins. We describe a method for the simultaneous quantitation of the aromatic amino acids in purified proteins. We used second-derivative ultraviolet spectroscopy coupled with a statistically weighted multicomponent analysis. Use of the second derivative virtually eliminated interference from light scattering and from cystine. Empirical selection of model compounds obviated the problem of wavelength shifts. The models are N-acetylphenylalanine ethyl ester in 6 M guanidine for phenylalanine, N-acetyltyrosine ethyl ester in 55% methanol for tyrosine, and mellitin in 6 M guanidine for tryptophan. This method permits accurate, rapid quantitation of phenylalanine, tyrosine, and tryptophan in intact, denatured proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2600-6
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Quantitation of aromatic residues in proteins: model compounds for second-derivative spectroscopy.
pubmed:publicationType
Journal Article