The Structure of the Ultraviolet Absorption Spectra of Certain Proteins and Amino Acids

Abstract

The ultraviolet absorption of the proteins in the region above 2500 A. comprises a broad band with its maximum about 2800 A. The spectrophotometric studies of Judd Lewis (1), Smith (2), and Smith and Marrack (3) have indicated the main quantitative features of this band without, however, disclosing evidence of finer structure. Indeed, with the exception of Spiegel-Adolf and Krumpel (4), who were able to distinguish several maxima in the absorption band of serum albu. rain, those investigators who have used the arc between metallic electrodes, in air, as the source of radiation have not discovered any details of structure. Vl~s and Prager (5) on the other hand found a band system consisting of nine narrow bands in serum albumin, when using the hydrogen discharge tube, which emits a continuous spectrum in the ultraviolet. With such a tube as source Ross (6) has Observed a similar resolution in the absorption bands of gelatin and several other proteins, and Lavin and Northrop (7) have found narrow bands in the absorption of crystalline pepsin.The ultraviolet absorption of the amino acids has likewise been extensively investigated. Although the aliphatic amino acids do not show appreciable absorption above 2500 A., the aromatic amino acids tyrosin, tryptophan, and phenylalanine give absorption in the same spectral region as the proteins, as shown by Dh6r6 (8), Ward (9), Smith (2), Gr6h and Han~k (10) and others. The absorption band of the proteins has in consequence been generally attributed to the content of these amino acids.

Experimental evidence that invasive grasses use allelopathic biochemicals as a potential mechanism for invasion: chemical warfare in nature

“…Further biochemical analysis indicated little difference between A. gerardii and B. ischaemum leachate. Maximum absorbency of both leachates exhibited readings at~280 nm, indicating the presence of proteins (Coulter et al 1936). While aqueous and organic solubility were similar for A. gerardii and B. ischaemum leachate, it is possible that the allelopathic biochemicals are not pigmented, and may be organic soluble.…”

The state of tyrosine in egg albumin and in insulin as determined by spectrophotometric titration

“…It contains 12-5 % of tyrosine [du Vigneaud, 1938] and no tryptophan; 12-5% of cystine, which is all present in the disulphide form; and some phenylalanine. The ultra-violet absorption spectrum of insulin has been examined by several authors, and was found to resemble that of tyrosine [Kuhn, Eyer & Freudenberg, 1931;Coulter, Stone & Kabat, 1936;Graubner, 1938].…”

Study of immunoglobulin ‘G’ with ultra violet spectroscopy in Duchene muscular dystrophy and Alzheimer’s disease

“…al. [43] and they have reported that aliphatic amino acids do not show absorption above 250 nm. Tyrosine tryptophan and phenylalanine show spectrum of absorption in the same spectral region as the proteins.…”