Proteins : lectures given in the United States of America in 1924 / by S.P.L. Sørensen.

  • Sørensen, S. P. L. (Soren Peter Lauritz), 1868-1939.
Date:
1925
Catalogue details

Licence: In copyright

Credit: Proteins : lectures given in the United States of America in 1924 / by S.P.L. Sørensen. Source: Wellcome Collection.

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    in pure water are really split off and the remaining substance will consequently show—at least approximately—a constant solubility in water, independent of the amount of globulin em- ployed. Thus Edwin /. Cohn5, in a series of carefully con- ducted and recently published experiments, has found that the solubility of well washed euglobulin in pure water corresponds to about 1.2 mg. globulin nitrogen per 100 cc. saturated solu- tion. We have been able to obtain exactly similar results, but if the purification of the globulin was continued, and was con- ducted not only by washing with water, but also by reprecipi- tation by means of neutral salt solutions, the reprecipitated globulin exhibited a considerably decreased solubility in water. Furthermore, as shown in Diagram 5, such an adequately re- precipitated fraction B^ exhibits an approximately constant solubility in 0.02 N sodium chloride solution, which is lower than the solubility in pure water stated by Cohn. However, even a substance such as Bvi cannot be regarded as a pure euglobulin; it exhibits indeed a fairly constant solu- bility in water and such weak sodium chloride solutions as 0.02 N, but in stronger salt solutions, where the dissociation of pseudoglobulin complexes can be carried still further, such a globulin preparation as Bvi shows a solubility dependent on the amount of globulin employed. On account of lack of material, we have unfortunately not been able to conduct such a solu- bility experiment with Bvi, but we have done so with another preparation called a&4. The globulin sample aa4 was purified by means of a series of reprecipitations, and was consequently one of the most sparingly soluble globulin fractions with which we have had to deal. With this sample of globulin a series of solubility BJ. of Gen. Physiol. 4, 697 [1922].