Patent ID: 7807435

Claim:
A method for the purification of alpha-1 proteinase inhibitor (a1PI) from a protein precipitate, comprising the steps of a. providing a frozen protein precipitate comprising a1PI, wherein the frozen protein precipitate comprises at least one Cohn fraction selected from the group consisting of Cohn fraction IV 1 , Cohn fraction IV 4 , Cohn fraction IV 1 +IV 4 and Cohn fraction IV 1,4 , b. thawing the protein precipitate at an ambient temperature of 2-25° C. until the protein precipitate has reached ambient temperature, without adding a suspending solvent, c. maintaining the thawed protein precipitate for at least 15 h (hours) at an ambient temperature of 2-25° C., and d. suspending the thawed, incubated precipitate of step c in a wash solution, and washing the protein precipitate; and e. extracting and purifying a1PI from the thawed, washed protein precipitate of step d.