PURPOSE: Provided is a method for the adsorption of proteins by using crosslinked methacrylic anhydride copolymer beads useful for an adsorbent, a material for affinity chromatography, ion exchange resin and precursors thereof. CONSTITUTION: The method for the adsorption of proteins onto copolymers functionalized with functional groups having affinity to proteins comprises the step of contacting proteins with a poly(methacrylic anhydride)-based copolymer in the form of crosslinked spherical copolymer beads having a particle size of 10 micrometers to 2 mm. The protein is aqueous suspension and the beads are microporous. Preferably, the copolymer is functionalized with carboxylic acid functional groups.
