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Occurrence of Ornithine in Sulphur-deficient Flax and the Possible Place of Ornithine and Citrulline in the Arginine Metabolism of Some Higher Plants


ALTHOUGH arginine has been recognized as a constituent of higher plants for many years, both as a structural unit in the protein and as the free amino-acid, two other components of the ‘ornithine cycle’ of animals, citrulline and ornithine, were not considered to be normal constituents of these plants. Wada, in 1930, isolated citrulline from Citrullus vulgaris Schrad.; but it was not again reported in higher plants until 1952, when Virtanen and Miettinen1 detected it in Alnus incana L. and Alnus glutinosa L. Citrulline is now known to occur as a free amino-acid in plants of a number of families.

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  1. 1

    Virtanen, A. I., and Miettinen, J. K., Nature, 170, 283 (1952).

  2. 2

    Philpott, M. W., Chem. Abs., 45, 9292b (1948).

  3. 3

    James, W. O., New Phytol., 48, 172 (1949).

  4. 4

    Virtanen, A. I., and Linko, P., Acta Chem. Scand., 9, 531 (1955).

  5. 5

    Coleman, R. G., Austral. J. Biol. Sci., 10, 50 (1957).

  6. 6

    Curzon, G., and Giltrow, J., Nature, 172, 356 (1953).

  7. 7

    Srb, A. M., and Horowitz, N. H., J. Biol. Chem., 154, 129 (1944).

  8. 8

    Coleman, R. G., and Hegarty, M. P., Nature, 179, 376 (1957).

  9. 9

    Ratner, S., Symposium on Amino-acid Metabolism, 251, edit. by McElroy, W. D., and Glass, H. B. (Johns Hopkins Press, Baltimore, 1955).

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