Detection of proteins and phenol in DNA samples with second-derivative absorption spectroscopy.
We have employed near-uv second-derivative spectra of DNA, N-acetyl-L-tryptophanamide, N-acetyl-L-tyrosinamide, N-acetyl-L-phenylalanine ethyl ester, and phenol in a matrix least-squares multicomponent analysis algorithm to detect the presence of tryptophan, tyrosine, phenylalanine, and/or phenol in DNA preparations. With this method, each of these compounds can be detected in a DNA sample (absorbance, 0.1) at absorbance levels of less than 0.002. In practice, the presence of proteins can be detected at absorbance levels of less than 0.003. Using second-derivative spectra of proteins, contents of mixtures of proteins and DNA can be determined with less than 1% error. Mixtures of DNA and RNA can also be quantitatively analyzed with an error of approximately 2%. This technique can be easily implemented with computer-controlled spectrophotometers equipped with standard spectral analysis software. With prerecorded standard spectra, the time of analysis does not exceed a few seconds.
Mach
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Department of Molecular Biology, University of Wyoming, Laramie 82071.
Middaugh
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Lewis
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D000818:Animals; D004247:DNA / Q000032:analysis*; D006801:Humans; D019800:Phenol; D010636:Phenols / Q000032:analysis*; D010649:Phenylalanine / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D012313:RNA / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014364:Tryptophan / Q000032:analysis; D014443:Tyrosine / Q000032:analysis
D010636:Phenols; D011506:Proteins; D019800:Phenol; D014443:Tyrosine; D010649:Phenylalanine; D012313:RNA; D014364:Tryptophan; D004247:DNA