Hydrolysis of excelsin / by Thomas B. Osborne and S.H. Clapp.

  • Thomas Burr Osborne
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: Hydrolysis of excelsin / by Thomas B. Osborne and S.H. Clapp. 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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    // Reprinted from the American Journal of Physiology- Vol. XIX.—June i, 1907. — No. I. HYDROLYSIS OF EXCELSIN.1 By THOMAS B. OSBORNE and S. H. CLAPP. [Front the Laboratory of the Connecticut Agricultural Experiment Station.] HE greater part of the protein substance of the Brazil-nut (Bertholletia excelsd) consists of the globulin excelsin which may be obtained in beautiful hexagonal crystals when the protein sepa- rates slowly from solution. These crystals have no effect on polarized light, and, as Maschke2 states, “undoubtedly belong to the regular system.” The same form would result if an octahedron were cut parallel to two opposite faces. As it is possible to obtain a large quantity of this globulin in a perfectly homogeneous crystallized con- dition, and as excelsin is also precipitated by ammonium sulphate,3 between comparatively narrow limits, the opportunity is presented of obtaining a protein preparation which offers a better guarantee of chemical individuality than do amorphous preparations of other The results of this hydrolysis of excelsin, like that of crystallized oxyhaemoglobin of the horse blood made by Abderhalden,4 shows that excelsin yields as many amino acids as most of the other chemically less well defined protein preparations. In making our preparation of excelsin for this hydrolysis great care was taken to obtain a product which consisted wholly of per- fectly formed crystals. In the preparation of this excelsin we received valuable assistance from Mr. I. F. Harris, for which we here wish to express our thanks. The character of the material used for the hydrolysis is best shown by the following microphotographs, for which we thank Prof. E. T. Reichert, of the University of Pennsylvania. 1 The expenses of this investigation were shared by the Connecticut Agricul- tural Experiment Station and the Carnegie Institution of Washington, D. C. 2 Maschke : Journal fiir praktische Chemie, 1858, lxxiv, p. 436. 8 Cf. Osborne and Harris : This journal, 1905, xiii, p. 436. 4 Abderhalden : Zeitschrift fiir physiologische Chemie, 1903, xxxvii, p. 484. proteins. S3