The alleged formation of adrenine from tyrosine / by A.J. Ewins and P.P. Laidlaw.

  • Ewins, Arthur James.
Date:
[1910?]
Catalogue details

Licence: Public Domain Mark

Credit: The alleged formation of adrenine from tyrosine / by A.J. Ewins and P.P. Laidlaw. Source: Wellcome Collection.

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    [Reprinted from the Journal of Physiology, Vol. XL. No. 3, May 11, 1910.] THE ALLEGED FORMATION OF ADRENINE FROM TYROSINE. By A. J. EWINS and P. P. LAIDLAW. (From the Wellcome Physiological Research Laboratories.) A PAPER by Halle1 appeared in 1906 in which he brought forward some evidence for the formation of adrenine from tyrosine. He prefaces his experimental results with some theoretical considerations as to the possibility of such formation. The requisite changes consist of four steps. 1. The introduction of a hydroxyl group into the benzene ring, for which he cites among other examples the formation of homogentisic acid from tyrosine in alcaptonuria. 2. The elimination of C02 from an amino-acid to form an amine, for example, the production of phenylethylamine from phenylalanine, and the formation of parahydroxyphenylethylamine from tyrosine. 3. The methylation of nitrogen. An analogous change is met with in the formation of methyl pyridylammonium hydroxide from pyridine. 4. The introduction of a hydroxyl group into an aliphatic chain. As an example he cites the formation of /3-oxybutyric acid from the higher fatty acids. Without criticising these theoretical speculations in detail we may point out that the fourth step is precisely the point at which Knoop2 found that the oxidation in the (3 position stopped short. Aromatic derivatives of the lower fatty acids were metabolised to benzoic or phenyl acetic acid according as there was an odd or even number of carbon atoms in the side chain. Halle’s experiments consisted in incubating finely minced fresh suprarenal glands with tyrosine under antiseptic conditions. Control experiments without tyrosine were carried out under the same con¬ ditions. At the end of six days’ incubation at 37° the proteins were 1 W. L. Halle. Beitr. z. chem. Physiol, u. Path. vm. p. 276. 1906.