Patent ID: 7270972

Claim:
A method for purifying the α-subunit originating from an oligomeric protein Crotalus horridus horridus B (CHH-B) having disulfide bonds within a subunit and between subunits, which comprises: (a) refolding the α-subunit by denaturing the oligomeric protein or its α-subunit in a solution comprising a reducing agent and a protein-denaturing agent and removing the reducing agent and the denaturing agent from the solution in the presence of polyoxyalkyl polyether having a functional group that reacts with a thiol group to allow the α-subunit to bind to the polyoxyalkyl polyether via the reaction between the thiol group of the α-subunit and the functional group of the polyoxyalkyl polyether that reacts with a thiol group; and (b) isolating the α-subunit of the Crotalus horridus horridus B (CHH-B) that is bonded to the polyoxyalkyl polyether from the solution.