Methods for separating soluble selenoglycoproteins
The invention relates to soluble selenium compositions and methods of production, separation and purification thereof. In particular the present invention provides methods of preparing water soluble selenoglycoproteins (e.g., via extracting selenoglycoproteins from selenium enriched yeast), methods of supplementing a selenium deficient composition via admixing water soluble selenoglycoproteins with the selenium deficient composition, compositions comprising the water soluble selenoglycoproteins and methods of administering the same.
1. A method for preparation of soluble selenoglycoproteins comprising:
a) providing selenium enriched yeast;
b) exposing the selenium enriched yeast to acidic conditions followed by centrifugation to generate
i) a pellet comprising acid insoluble material; and
ii) a liquid phase comprising the extract of selenium enriched yeast soluble under the acidic conditions;
c) precipitating selenoglycoproteins from the liquid phase comprising the extract of selenium enriched yeast soluble under the acidic conditions via raising the pH of the liquid phase; and
d) separating the precipitated selenoglycoproteins from the liquid phase.
2. The method of claim 1 , wherein the acidic conditions are obtained using acidic buffer or the addition of an acid.
3. The method of claim 2 , wherein the acid is hydrochloric acid.
4. The method of claim 1 , wherein exposing the selenium enriched yeast to acidic conditions comprises exposing the selenium enriched yeast to a pH between 1.5 and pH 6.5.
5. The method of claim 4 , wherein the pH is 1.5.
6. The method of claim 1 , wherein the selenium enriched yeast are exposed to acidic conditions for between one and twenty-four hours.
7. The method of claim 1 , wherein the selenium enriched yeast are exposed to acidic conditions for between five and ten hours.
8. The method of claim 1 , wherein the selenium enriched yeast are exposed to acidic conditions for about 8 hours.
9. The method of claim 1 , wherein exposing the selenium enriched yeast to acidic conditions occurs at a temperature greater than room temperature.
10. The method of claim 9 , wherein the temperature is between 50° C. and 100° C.
11. The method of claim 9 , wherein the temperature is between 70° C. and 85° C.
12. The method of claim 9 , wherein the temperature is 80° C.
13. The method of claim 1 , wherein selenoglycoproteins are precipitated from the liquid phase at a variety of pH conditions to generate multiple pH dependent fractions of soluble selenoglycoproteins.
14. The method of claim 13 , wherein the multiple pH dependent fractions of soluble selenoglycoproteins are generated at pH values of 1.85, 3.0, 4.0 and 6.0.
15. The method of claim 1 , wherein separating the precipitated selenoglycoproteins from the liquid phase comprises centrifugation to form a pellet of the precipitated selenoglycoproteins followed by removal of the liquid phase from the precipitated selenoglycoproteins.
16. The method of claim 1 , wherein the method is used to create a fraction of soluble selenoglycoproteins precipitated at a value selected from the group consisting of pH of 1.85, 3.0, 4.0 and 6.0.
17. The method of claim 1 , wherein the selenium enriched yeast are dried, nonviable selenium-enriched yeast containing 2% or less inorganic selenium.