| 摘要 |
A product of enhanced lactogenic activity is prepared from a multicomponent prolactin composition derived from sheep pituitary glands by chromatographing a solution thereof in an (ethylenedinitrilo)-tetraacetic acid-tris-(hydroxymethyl)aminomethane - borate buffer (pH 9.0) on a column of diethylaminoethyl-cellulose to obtain fractions containing the required substance and not more than one other component, collecting and concentrating such fractions, re-chromatographing the concentrate under the same conditions and recovering the product with enhanced lactogenic activity from fractions containing only that material as shown, for example by electrophoresis. The said material is stated to behave as a homogeneous protein in free boundary electrophoresis, to have an electrophoretic mobility of 3.80 X 10-5 cm.2 sec.-1 volt-1 in a glycine-sodium hydroxide buffer at pH 10.0, an isoelectric point of pH 5.75 (determined by free boundary electrophoresis), a sedimentation constant of 2.18S as a single, sharp, symmetrical boundary in glycine-sodium hydroxide buffer at pH 10.0, and to have threonine as the N-terminal amino acid and cysteine as the C-terminal amino acid. The Specification also describes a process for obtaining the multi-component prolactin from sheep pituitary glands by extracting the ground glands with acetone/HCl, filtering and standing the filtrate (diluted with acetone) over night, collecting the precipitate formed, re-dissolving the precipitate in acetone and freeze-drying the solution, dissolving the product in aqueous HCl (pH 3.0) and removing the insoluble material, adding NaCl to the resulting solution, collecting the precipitate and dissolving it in aqueous NaOH (pH 9.0), adjusting the pH to 6.3 (with HCl), removing insoluble material by centrifugation, adjusting the pH of the solution to 5.6 (with HCl), collecting the precipitate formed on standing, dissolving the precipitate in water and freeze-drying the solution.
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