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May
Uv Absorbance Of Amino Acids. A 1000 x 01 x 1 10. Proteins usually show absorption maxima between 275 and280nmFigure 1whicharecausedbytheabsorbance of the two aromatic amino acids tryptophan Trp and tyrosineTyrandtoasmallextentbytheabsorbanceof cystineieofdisulfidebondsTheabsorbancesofTrp and Tyr depend on the microenvironment of their chromophores and they are slightly red-shifted when. As demonstrated in Figure 2 aromatic amino acids and proteins absorb UV light with two distinct peaks. Different amino acids absorb at different wavelengths The extinction coefficients differ widely The amino acid composition of proteins varies widely Nucleic acids absorb strongly near 260 nm.
In the near UV 290 nm all the tested acids show a common absorption maximum and good sensitivities. 255 and 285 rim EXPERIMENTAL Apparatus and reagents UV measurements were made in a 1-cm quartz cell in a Hitachi UV 150 spectrophotometer with a UV 150-20 data processor. In the visible region at 404 nm the sensitivities of the α-amino acids are very similar to those observed at 570 nm. Fraction transmitted. The configurational stability of the protein molecule depends entirely on extra-valence. Different amino acids absorb at different wavelengths The extinction coefficients differ widely The amino acid composition of proteins varies widely Nucleic acids absorb strongly near 260 nm.
Deionized water was used throughout.
The amino acid dithiocarbamates formed are water soluble and show UV absorption at ca. 255 and 285 rim EXPERIMENTAL Apparatus and reagents UV measurements were made in a 1-cm quartz cell in a Hitachi UV 150 spectrophotometer with a UV 150-20 data processor. Complementary UV-absorption of mycosporine-like amino acids and scytonemin is responsible for the UV-insensitivity of photosynthesis in Nostoc flagelliforme Mycosporine-like amino acids MAAs and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. The peak centered on 280 nm is the result of absorbance by the aromatic ring portion of their structure. This absorption is due to the aromatic amino-acids present in the protein. Cence UV absorption is also known to be sensitive to the conforma-tional changes in proteins 34.