Hydrolysis of hordein : by Thomas B. Osborne and S.H. Clapp.

  • Thomas Burr Osborne
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: Hydrolysis of hordein : by Thomas B. Osborne and S.H. Clapp. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The filtrate from barium phosphotungstate, freed from barium with sulphuric acid, ^separated sparingly very thin prisms of brilliant mother-of-pearl lustre, which proved identical with a substance re- cently isolated by us1 by a similar method from gliadin, and which we feel justified in regarding as a dipeptide of proline and phenylala- nine. When heated side by side with a pure preparation from gliadin, the substance decomposed simultaneously with the latter at about 2490 (uncorr.), and when mixed the decomposition point was not lowered. Histidine. Fifty grams of hordein, equal to 44.91 gm. ash and moisture free, were hydrolyzed and the bases determined according to the method of Kossel and Patten. The solution of the histidine was made up to 500 c.c. and found to contain nitrogen equal to 0.5770 gm. of histi- dine or 1.28 per cent. Nitrogen, 100 c.c. solution required 3.13 c.c. 5/7 N—HC1 = 0.0313 gm. N = 0.1565 gm- N in 500 c.c. = 0.5770 gm. histidine = 1.28 per cent. The histidine was converted into the dichloride which decomposed at 2320—2330. Chlorine, 0.0770 gm. subst., gave 0.0963 gm. AgCl. Calculated for C6Hn02N8Cl2 = Cl 31.14 per cent. Found = Cl 30.92 “ “ Arginine. The solution of the arginine was made up to 1000 c.c. and found to contain nitrogen equal to 0.972 gm. arginine or 2.16 per cent. Nitrogen, 100 c.c. solution required 2.9 c.c. 5/7 N — HC1 = 0.0290 gm. N = 0.2900 gm. N in 1000 c.c. = 0.9 gm. arginine. Adding 0.072 gm. for solubility of arginine silver = 0.972 gm. = 2.16 per cent. The arginine was converted into the copper nitrate double salt. Water, 0.1069 gm. subst., air dry, lost 0.0099 gm. H20. Calculated for C12H2804N8Cu(N08)2 • 3 H20 = H20 9.16 per cent. Found = H„0 9.26 “ “ Copper, 0.0962 gm. subst., dried at ioo°, gave 0.0143 gm- CuO. Calculated for C]2H2804N8Cu(N08)2 = Cu 11.87 Per cent. Found = Cu 11.87 “ “ 1 Osborne and Clapp: This journal, 1907, xviii, p. 123.