Abstract
THE amino-acid tryptophan can be metabolized along two different pathways (Fig. 1), each of which is characteristic for a particular type of tissue. As the substrate of L-tryptophan oxygenase, it is a source of pyridine nucleotide. This metabolic pathway occurs only in the liver1. Alternatively, tryptophan can be hydroxylated in the 5-position and further metabolized to yield serotonin and melatonin. Serotonin is synthesized mainly by cells derived from the embryonic neuroectoderm2; melatonin production, which in mammals is restricted to the pineal gland, also occurs in the eye and brain of amphibia3,4.
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Knox, W. E., and Mehler, A. H., J. Biol. Chem., 187, 419 (1950).
Lovenberg, W., Jequier, E., and Sjoerdsma, A., Adv. Pharmacol., 6, 21 (1968).
Lerner, A. B., Case, J. D., and Takahashi, Y., J. Biol. Chem., 235, 1992 (1960).
Wurtman, R. J., and Axelrod, J., Adv. Pharmacol., 6, 141 (1968).
Stearns, R. N., and Kostellow, A. B., in A Symposium on the Chemical Basis of Development (edit. by McElroy, W. D., and Glass, B.), 448 (Johns Hopkins Press, 1958).
Kostellow, A. B., and Morrill, G. A., Biophys. J., 8, A89 (1968).
Morrill, G. A., and Kostellow, A. B., J. Cell Biol., 25, 21 (1965).
Knox, W. E., in Methods in Enzymology, 2 (edit. by Colowick, S. P., and Kaplan, N. O.), 242 (Academic Press, 1955).
Udenfriend, S., Fluorescence Assay in Biology and Medicine, 160 (Academic Press, 1962).
Klein, D. C., and Notides, A., Anal. Biochem., 31, 480 (1969).
Bratton, A. C., and Marshall, E. K., J. Biol. Chem., 128, 537 (1939).
Quay, W. B., Anal. Biochem., 5, 51 (1963).
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KOSTELLOW, A., MORRILL, G. Tryptophan Induction of the Serotonin and Kynurenine Pathways in the Early Amphibian Embryo. Nature New Biology 231, 119–121 (1971). https://doi.org/10.1038/newbio231119a0
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DOI: https://doi.org/10.1038/newbio231119a0