The ultra-violet absorption spectra of certain aromatic amino-acids, and of the serum proteins

The absorption spectra of the aromatic amino-acids and of the serum proteins have been investigated by Dhéré, 1909 (1), who obtained values for the wave-lengths in close accordance with those found by subsequent workers; he was unable to measure the extinction coefficients, sine at the time no suitable apparatus had been devised. He further noted that the absorption spectrum of tyrosine moved towards the red and tryptophane were responsible for the absorption spectrum of protein. In 1916, Kober (2) investigated the absorption bands of the aromatic amino-acids. Ward (3) in 1923, and Marchlewski (4) in 1925, made use of the rotating sector to measure the extinction coefficients of tyrosine, tryptophane, and phenyl-alanine. The absorption spectrum of tryptophane has also been measured by Abderhalden and Hass (5). In 1922, Judd Lewis (6) measured the absorption spectra of the serum proteins. Stenström and Reinhard (7) have confirmed the work of Dhéré, showing that the aromatic amino-acids present in the protein molecule were responsible for its absorption spectrum.