Investigations of Nitrogen Compounds and Nitrogen Metabolism in Plants. Iii. γ-Aminobutyric Acid in Plants, With Special Reference to the Potato Tuber and a New Procedure for Isolating Amino Acids Other Than α-Amino Acids

New Amino Acids of Plants

“…Of these new acids, y-aminobutyric acid was the first to be recognized as a constituent of higher plants (Dent et al 1947; Steward, Thompson & Dent, 1949). When proof of its existence was obtained by isolation (Westall, 1950;Reed, 1950;Synge, 1951; Thompson, Pollard & Steward, 1953), it caused little surprise since previously it was well known that glutamic decarboxylase was present in a wide variety of plants (Okunuki, 1937; Schales, Mims & Schales, 1946). Later work has indicated that y-aminobutyric acid is often very abundant in plants and that it is very widely distributed.…”

“…Their transaminase activity towards other amino acids remains largely unchanged and so a specific rather than a general change in the enzyme complement of the cells occurs as a result of yaminobutyric acid nutrition. Thompson et al (1953) report that y-aminobutyric acid, supplied as a sole source of nitrogen, can support some growth of excised carrot tissue. They inferred that the nitrogen of the amino acid probably entered the tissue protein, although this was not proved.…”

A Quantitative Chromatographic Study of Nitrogenous Components of Shoot Apices

“…Prominent among these was the use of previously washed, buffered papers and a final technique which ensured the quantitative development on the paper of the ninhydrin color which was then determined by a procedure already described (Thompson et al, 1951). stream of air and redissolved in a small volume of water prior to chromatographic examination.…”

“…The now familiar precautions to ensure good separation were adopted as well as the procedures prescribed for the quantitative determination of the amino acids and amides. Prominent among these was the use of previously washed, buffered papers and a final technique which ensured the quantitative development on the paper of the ninhydrin color which was then determined by a procedure already described (Thompson et al, 1951). In this way, amounts of the order of 30-50 p.g.…”

“…Analytical and chromatographic methods.-These methods followed the pattern being employed in the Cornell Laboratories for the investigation of nitrogen compounds and nitrogen metabolism in plants (Steward and Thompson, 1950;Thompson and Steward, 1951). All the material, dissected and freeze-dried at Harvard, was subsequently extracted at Cornell.…”