THE AMINO ACIDS OF ALFALFA AS REVEALED BY PAPER CHROMATOGRAPHY WITH SPECIAL REFERENCE TO COMPOUNDS LABELLED WITH S35

Publisher Website
Google Scholar
Abstract
The free and combined amino acids of alfalfa leaves have been examined by the methods of paper chromatography and autoradiography for S35 which was introduced into the plants in the form of sulfate via the roots. Aspartic and glutamic acids, alanine and serine were the conspicuous amino acids which were detected free in alfalfa, and the amides glutamine and asparagine were also prominent. Valine, the leucines, tyrosine and alpha-amino butyric acid were all readily detectable. The only free basic amino acid detected was arginine. The free-sulfur containing compounds consisted of cystine (detected as cysteic acid) and substances, most probably glutathione, which yielded cystine on hydrolysis. Methionine and its oxidation products, the sulfoxide and sulfone, were not detected in the free state. The combined amino acids of alfalfa were examined after hydrolysis of (a) an alcohol-insoluble fraction, (b) a heat coagulum of a water extract, and (c) a water-, alcohol-, and acid-insoluble fraction. These amino acids were those commonly found in proteins; valine and the leucines were more prominent in the hydrolysates than in the free state; glycine, lysine, threonine, methionine and proline were detected only in the protein hydrolysates. Hydroxy-proline appeared only in the hydrolysate of (c), phenylalanine only in the hydrolysate of (b). The S35-containing compounds in these hydrolysates were methionine sulphone and sulfoxide from methionine and cysteic acid from cystine. Certain other S compounds were detected by autoradiographs of chromato-grams. None of these was taurine.