Process for isolating a fibrin-stabilizing factor

Claim 1

A process for isolating a fibrin-stabilizing factor which comprises: a. extracting human placentae at a temperature from 0°C. to 20°C. with a dilute aqueous sodium chloride solution and removing solid contaminants from the extract; b. adding a dilute aqueous solution of diaminoethoxy-acridine lactate to said extract at a temperature from 5°C. to 20°C. and at a pH between 5.0 and 7.5 in an amount furnishing 6 to 10 grams of said lactate per 100 grams of protein content in said extract to form a first precipitate, and isolating said first precipitate; c. dissolving said precipitate at a temperature from 5°C. to 20°C. in a dilute solution of alkali metal chloride at a pH between 7.0 and 8.0, said solution containing about 5 percent, by weight of said alkali metal chloride, of a complexing agent selected from the group consisting of ethylene diamine tetraacetic acid and nitrilo-triacetic acid, and removing any insoluble substances from the solution; d. adding a quaternary ammonium base to the solution in an amount from 0.04 to 0.08 percent, by weight of the solution, at a temperature from 5°C. to 20°C. to form a second precipitate, and removing and discarding this second precipitate; e. adding a dilute aqueous solution of diaminoethoxy-acridine lactate to the solution at a temperature from 5°C. to 20°C. to form a third precipitate, and isolating said third precipitate; f. dissolving said third precipitate in a dilute solution of an alkali metal chloride at a temperature from 5°C. to 20°C. and at a pH between 7.0 and 8.0, said solution containing about 5 percent, by weight of said alkali metal chloride, of ethylene diamine tetraacetic acid or nitrilo-triacetic acid and removing any insoluble substances from the solution; g. adding 20 to 30 percent of solid ammonium sulfate to the solution to form a fourth precipitate, and isolating said fourth precipitate; h. forming a paste from said fourth precipitate and a dilute solution of ethylene diamine tetraacetic acid or nitrilo-triacetic acid and dialyzing said paste against tris(hydroxymethyl)-aminoethane/hydrochloric acid buffer containing ethylene diamine tetraacetic acid or nitrilo-triacetic acid and sodium azide, whereby the paste is solubilized; i. adjusting the pH of the dialyzed solution to 6.0 to form a fifth precipitate which is separated and discarded, and readjusting the pH to 7.0; j. gel filtering the solution on cross-linked dextran, eluting with tris(hydroxymethyl)-aminomethane/hydrochloric acid buffer containing ethylene diamine tetraacetic acid or nitrilo-triacetic acid and sodium azide, and collecting and combining active fractions having an activity of more than 2 units of fibrin-stabilizing factor; k. adding sufficient solid ammonium sulfate to the collected active fractions to form a sixth precipitate containing the fibrin-stabilizing factor, and isolating said sixth precipitate; l. dissolving said sixth precipitate in a neutral tris(hydroxymethyl)-aminomethane/ethylene diamine tetraacetic acid buffer; m. dialyzing the solution against neutral tris(hydroxymethyl)-aminomethane/ethylene diamine tetraacetic acid buffer; n. adjusting the pH of the dialyzed solution to 5.0 to precipitate the fibrin-stabilizing factor and isolating the precipitate.