The proteins of the pea (Pisum Sativum) / by Thomas B. Osborne and Isaac F. Harris.

  • Osborne, Thomas B. (Thomas Burr), 1859-1929.
Catalogue details

Licence: Public Domain Mark

Credit: The proteins of the pea (Pisum Sativum) / by Thomas B. Osborne and Isaac F. Harris. 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.

    2/8 (page 214)
    extracted by sodium chloride solution and that several of the preparations previously called legumin were certainly different substances. The investigations of many different leguminous seeds made in this laboratory have shown that from the pea, Pisum Sativum, horse bean, Vida Faba, lentil, Ervum lens, and vetch, Vida Saliva, preparations of the globulin can be obtained which agree strictly in properties and composition with one another but are distinctly different from those obtained from seeds of the genus Phaseolus and other kinds of legumes. The writer has therefore designated this protein as legumin, for it undoubtedly represents the substance to which earlier investi- gators most frequently intended to apply this name. In the seeds of the pea, horse bean and lentil the legumin is associated with another protein which has been called vicilin by the writer. The history of legumin and the characteristics of the proteins of the seeds above mentioned has been discussed in papers from this laboratory.^ Legumelin is an albumin-like protein which is not precipitated by dialysis and is coagulated by heating its solutions to about 8o°. The greater part of the legumelin separates between 6o° and 65° but its complete coagulation is not effected below 80°. The composition of legumelin is distinctly different from that of legumin or vicilin. In properties and composition it closely resembles leucosin found in the embryo of wheat and it is proba- bly a tissue protein rather than a reserve food protein of the endo- sperm. Proteins of the same composition and properties as the legumelin of the pea have been found in a large number of other leguminous seeds, e.g., lentil, horse bean, vetch, adzuki bean, cow pea and soy bean. As a complete separation of legumin from vicilin by fractional precipitation from sodium chloride solutions can be obtained only by the sacrifice of a large part of the mixed globulins and the expenditure of much time and labor we have studied the results obtained by fractional precipitation with ammonium sulphate and found that this method yields products of the same proper- ties and ultimate composition as those previously obtained from ‘Cf. Osborne and Campbell: Jotirn. Ayner. Chem. Soc., xviii, p, 583, 1896. Ibid., XX, pp. 348, 362, 393, 406 and 410, 1898.