Patent ID: 9487566
Filing Date: 2016-11-08
CPC Classification: C07K

Claim Text:
1. A method for purifying antithrombin, comprising a first chromatographic process including the following processes of (a) to (c): (a) a process of contacting a composition comprising the antithrombin and impurities comprising sialidase with an anion exchange carrier so that the antithrombin and the impurities are adsorbed to the anion exchange carrier; (b) a process of washing the anion exchange carrier to which the antithrombin and the impurities are adsorbed using a first buffer weakening affinity of the impurities for the anion exchange carrier so as to remove the impurities and to inhibit the degradation of sialic acids by inhibiting the activity of sialidase, said first buffer containing 0.1 to 1 mol/L of glycine so as to remove the impurities, and said first buffer being one or more selected from the group consisting of phosphate, citrate, acetate, succinate, maleate, borate, Tris, HEPES, MES, PIPES, MOPS, TES, and Tricine; and (c) a process of eluting the antithrombin from the anion exchange carrier by using a second buffer which is one or more selected from the group consisting of phosphate, citrate, acetate, succinate, maleate, borate, Tris, HEPES, MES, PIPES, MOPS, TES, and Tricine so as to purify antithrombin in which the number of bound sialic acids is 70% or more of the maximum number to be added, wherein the maximum number to be added is 8 mol/mol for Antithrombin α form or 6 mol/mol for Antithrombin β form.