Protein adsorbent

A method for adsorbing a protein from an aqueous solution or dispersion of the protein which comprises contacting an aqueous solution or a dispersion of a protein with a porous copolymer obtained by copolymerizing a monomer mixture comprising 2 to 98% by weight of at least one cyano group-containing monomer represented by the following general formula (A):

• ##STR6## wherein R stands for a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a halogen atom, a cyano group, a methoxy group, an acetoxyl group, or an unsubstituted or substituted phenyl group represented by the formula ##STR7## wherein R' stands for a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a halogen atom, a cyano group, a methoxy group or an acetoxyl group), and 2 to 98% by weight of at least one cross-linkable monomer having a plurality of CH.sub.2 .dbd.C<
• groups, said copolymer having an average pore diameter (d) of from 40 A to 9,000 A and a total pore volume of from 0.05 .sqroot.X ml to 1.5 .sqroot.X ml per gram of the copolymer in a dry state, in which X designates the weight proportion of said cross-linkable monomer expressed in terms of the percent by weight based on the total monomers, and being employed in an amount of 0.02 to 300 g per liter of said solution or said dispersion.