The identity of trimethylhistidine (histidine-betaine) from various sources / by George Barger and Arthur James Ewins.

  • Barger, George, 1878-1939
Date:
[1913?]
Catalogue details

Licence: Public Domain Mark

Credit: The identity of trimethylhistidine (histidine-betaine) from various sources / by George Barger and Arthur James Ewins. Source: Wellcome Collection.

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    (treating the aqueous solution of the dipicrate with one molecular proportion of sodium hydrate). The melting points of mixtures in all cases showed no depression. There can be no doubt, therefore, that the trimethylhistidine (histidine- betaine) obtained by us from ergothioneine is identical with that obtained by Reuter from Boletus edulis and with the synthetic base obtained by Kutscher. This result affords a further confirmation of the constitution assigned by us, on other grounds, to ergothioneine. For the isolation of the betaine of histidine we find that the preparation of the dipicrate is the most convenient method; this salt dissolves in about 25 parts of boiling water and readily crystallises in thin elongated rectangular plates with two molecules of water of crystallisation, and when air dry, melts at 123°-124°. In our previous paper [1911] the melting point of the aurichloride of the betaine was given as 171°. As the quantity of material at our disposal was at that time very small (a few centigrams only) we were unable to analyse this salt, but now, with a further supply of material, we find that the gold salt when pure melts at 184°, in agreement with the melting point as given by Kutscher and by Reuter. We also determined the rotation of the base recovered from Reuter’s dipicrate with the following result. Concentration of base (in aqueous solution as hydrochloride) = 0’39 per cent. Actual rotation measured aD = -f 0'40 (mean of 6 readings) in 2‘2 d.m. tube. Whence [a]D = -f 46'5C. In conclusion we may point out that the trimethylhistidines obtained from various sources are thus shown to be identical. This substance must be classed with the other naturally occurring betaines from amino-acids, such as * those from glycine, proline, oxy-proline, and tryptophane (i.e. ordinary betaine, stachydrine, betonicine and hypaphorine respectively). REFERENCES. Barger and Ewins (1911), J. Ghem. Soc. 99, 2396. Kutscher (1910), Zentr. Physiol. 24, 775. - (1912), Zentr. Physiol. 26, 869. Pyman (1911), J. Ghem. Soc. 99, 2172. Reuter (1912), Zeitsch. physiol. Ghem. 78, 167. Tanret (1909), J. Pharm. Chim. [vi], 30, 145.