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.

    5/37 (page 306)
    of the globulin, and many of those of the albumin, from the embryo contained various yet considerable quantities of this element, and when digested with pepsin, yielded insoluble pro- ducts having the characteristics of nuclein. 'The elementary composition of those preparations of the embryo-albumin which contained no phosphorus, or only traces, was the same as that of leucosin prepared from the whole seed, while the com- position of those embryo-albumin preparations which contained phosphorus differed from that of leucosin in proportion to the phosphorus present. Analyses of different preparations of embryo-globulin showed no agreement, even when corrected for ash. These facts led us to examine our extracts for nucleic acid, and having found this acid and determined its composition, it was seen that the differences just alluded to disappear if we assume the phosphorus to be present as nucleic acid and calcu- late the analyses free from this acid and from ash. In a paper recently published by one of us on “Some Definite Compounds of Protein Bodies” (Jour. Am. Chem. Soc., XXI, 486), it was shown that many, if not most preparations of so- called native proteids are, in fact, compounds of protein bodies with acids, and it was suggested that nucleoalbumins might prove to be similar phosphoric acid compounds. In that paper it was also shown that the crystallized globulin, edestin, obtained from hemp-seed, forms a compound with one, and another compound with two molecules of hydrochloric acid, both of which are crystalline, and that the preparations of this globulin as commonly obtained, are mixtures of these in vari- ous proportions. It was also shown that the protein molecule can combine with more than two molecules of acid, so that several multiple compounds of one acid with the same protein molecule can undoubtedly exist. That our preparations from the wheat-embryo are mixtures of two or more compounds is shown by the variable propor- tions of phosphorus which they contain. That phosphorus is a chief factor in determining the proportion of nuclein that sepa- rates during pepsin digestion is shown by the fact that the amount of nuclein 'found is always in close relation to the amount of phosphorus contained in the preparation.