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

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

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    \ V - / C U . ' THE PROTEINS OF THE PEA (Pisam Sativum) By THOMAS B. OSBORNE and ISAAC F. HARRIS. {From the Laboratory of the Connecticut Agricultural Experiment Station.) (Received for publication, May 9, 1907.) According to former investigations made in this laboratory the seeds of the garden pea {Pisum Sativum) contain three different proteins: Legumin, vicilin and legumelin. The two former are globulins of similar composition and properties which were sepa- rated from one another by fractional precipitation from sodium chloride solutions, the vicilin being more soluble than the legumin in dilute saline solutions while the legumelin remained in solution after dialysis and was separated by heating the solution to 80°. The most marked difference between legumin and vicilin was shown by the behavior of their solutions on heating. Sodium chloride solutions of legumin remain perfectly clear when heated to 100°, those of vicilin become turbid at 90°, at 95° a flocculent coagulum separates and when heated at 100° for some time the vicilin is almost completely coagulated. Legumin contains a little less car- bon and a little more nitrogen than vicilin and distinctly more sulphur. Vicilin contains less sulphur than any protein thus far isolated. By repeated precipitation the amount of sulphur was found to diminish from 0.23 per cent to 0.08 percent.^ The name legumin has long been used to designate various pro- tein preparations obtained from many of the leguminous seeds. Most of these preparations were formerly obtained by extraction with alkali and precipitation with dilute acid and therefore rep- resented products of doubtful character. Later investigations showed that most of these proteins were globulins which could be ' The expenses of this investigation were shared by the Connecticut Agricultural Experiment Station and the Carnegie Institution of Wash- ington, D. C. ’Cf. Osborne and Campbell: Journ. Amer. Chem. Soc., xx, p. 410, 1898.