Spectra of Some Amino Acids, Peptides, Nucleic Acids, and Protein in the Vacuum Ultraviolet

Abstract

The absorption spectra of several amino acids, peptides, nucleic acids, and a protein have been obtained down to 1450 A. The samples were in the form of thin films supported on calcium fluoride. All compounds studied had characteristic absorption spectra below 2000 A. In some cases, e.g., tryptophan, the absorption spectrum of the solid film showed pronounced difference from the spectrum of the molecules in solution. At 1900 A, the absorption coefficient of the protein chymotrypsin is the sum of the molecular extinction coefficients of its components. The instrument used was a vacuum grating‐monochromator with hydrogen discharge light source.