Bound amino acids of ryegrass: the isolation of amphoteric peptide-like substances of low molecular weight

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Abstract
A complex mixture of neutral amphoteric peptide-like compounds of low molecular weight has been isolated from the expressed juice of ryegrass. The bound amino acid residues account for less than 1% of the N of the expressed juice. The techniques used in the isolation included ion-exchange chromatography, partition chromatography and preparative paper electrophoresis. Pigments were difficult to remove. Nitrogenous bases similar in some of their properties to purines and pyrimidines occurred in several of the fractions. A group of substances with amino acid content mainly of leucine, isoleucine, valine, tyrosine and phenyla-lanine was isolated. They had similar chromatographic and electro-phoretic properties to leucyl peptides of low molecular weight. The presence of other groups of substances, containing a higher proportion of glutamic acid and aspartic acid and smaller amounts of most of the common amino acids, was observed. It was not possible, because of the small quantities available, to make a full characterization. The occurrence of adenine as a free base in grass is confirmed.