Patent ID: 9428544
Filing Date: 2016-08-30
CPC Classification: B01J,C07K

Claim Text:
1. A method for purifying a protein by a porous membrane having a substrate surface coated with a polymer having protein adsorption ability, comprising: an adsorption step of passing a stock solution containing an adsorption target protein through a pore direction from one surface to another surface of the porous membrane to allow the polymer to adsorb the adsorption target protein; and an elution step of passing an eluent through the porous membrane to allow the adsorption target protein that is adsorbed on the polymer to elute in the eluent, wherein in the elution step, at least one eluent is passed in an opposite direction with respect to the pore direction of passage of the stock solution in the adsorption step; wherein a degree of multilayering of the porous membrane is 1.1 or more, and the degree of multilayering is a value obtained by the following formula (3) where the equilibrium adsorption capacity is obtained by the following formula (4), when the stock solution comprising the adsorption target protein is passed through the porous membrane where C 0 : concentration of protein in stock solution [g/L]; C: protein concentration in passed solution of stock solution [g/L]; Q: cumulative amount of passed solution of stock solution [L]; Q W: weight of protein-adsorbing porous membrane [g]; and the theoretical single-layer adsorption capacity is obtained by the following formula (5) where S M : specific surface area of protein-adsorbing porous membrane [m 2 /g]; S M N