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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    That the preparations are not mixtures of already formed nuclein with ordinary proteid matter is shown by the difference in s’olubility and behavior of the original preparation from that of the nuclein derived from it. It would seem, then, that the nuclein obtained by pepsin digestion is not an original constituent of the extract nor of the cells of the embryo, but results through combination of several molecules of nucleic acid with one of protein. Accordingly we conclude that these phosphorus-containing preparations from the wheat embryo are mixtures of different protein nucleates and that when subjected to pepsin digestion, in consequence of the conversion of a part of the protein sub- stance into proteose, the proportion of nucleic acid to unaltered protein is increased, so that higher acid nucleates are formed which are insoluble in the digestive fluid. The grounds for these conclusions are given in the following detailed account of our investigation. The material at our command consisted of a quantity of wheat germs, a specially prepared product of the Pillsbury Mills, from which the bran and endosperm had been very thoroughly removed, which was kindly procured for us by Mr. David Chid- low of Chicago. The germ meal, which was prepared and sent to us in cold weather, was immediately extracted with petroleum naphtha and ground to a flour. I. The Nucleic Acid of the Wheat Embryo. We shall later show that the precipitate produced by saturat- ing the slightly acid aqueous extract of this wheat embryo meal with sodium chloride contains almost all the phosphorus of the extract. We accordingly extracted a large quantity of the meal with water, saturated the extract with sodium chloride and subjected the precipitate to a vigorous pepsin digestion. We thus obtained a considerable quantity of nuclein from which we prepared nucleic acid in the following manner; The nuclein was thoroughly washed with water and then dilute potash solution was added until all the nuclein had dis- solved and its solution become faintly alkaline to phenol- phthalein.