The nucleic acid of the embryo of wheat and its protein compounds.

  • Osborne, Thomas B. (Thomas Burr), 1859-1929.
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: The nucleic acid of the embryo of wheat and its protein compounds. 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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    while a slightly larger quantity, added before heating, entirely prevents the formation of this coagulum. Acetic acid and nitric acid give precipitates in the extracts which are not soluble in a reasonable excess of either of these acids. In order to determine definitely the relations of these variously obtained substances, we have made a large number of fractional precipitations under quite different conditions, an account of which we now give: An extract was made by treating 700 grams of germ meal with seven times its weight of water, straining through bolting cloth and filtering the fluid perfectly clear. This was slightly colored, perfectly neutral to litmus, alkaline to lacmoid and strongly acid to phenolphthalein. A portion of it was at once heated for one hour in a water bath at 60°, and the large coagulum produced was filtered out, washed thoroughly with hot water and with alcohol and dried over sulphuric acid, giving 24.0 grams of preparation 1. Another preparation was made by heating in a water batli at 65°, 2,000 cc. of a clear aqueous extract, obtained by treat- ing 3,000 grams of the germ meal with 9,000 cc. of water. The coagulum produced, when washed with hot water and alcohol and dried over sulphuric acid, weighed 62 grams, forming more than 9 p. c. of the oil-free germ meal. This is preparation 2. Another aqueous extract was heated at 65°, until all the proteid coagulable at this temperature had separated. The coagulum produced, when washed with hot water and alcohol was dried over sulphuric acid and found to weigh 16.68 grams. The filtrate from this coagulum, heated in a boiling water bath, yielded a second coagulum which, when washed and dried, formed preparation 3, weighing 4.9 grams. A portion of the extract, which yielded preparation i, was saturated with ammonium sulphate, the resulting precipi- tate was dissolved as far as possible in water, its solution filtered clear and dialyzed for four days. During this time a consider- able precipitate formed, that, when filtered out, was found to be insoluble in salt solution. The solution, filtered from that substance and dialyzed in running water until nothing more separated, was filtered and heated at 60°, which caused a coagu- lum. This coagulum, washed with hot water and with alcohol