PURPOSE: Provided is a method for simply and economically preparing reactive proteins by obtaining refolded proteins from cell-lysate including an inclusion body or a denaturant. CONSTITUTION: The method comprises : unfolding process involving cell lysis of a host cell containing an inclusion body typed proteins and adding a denaturant to the cell lysate; adsorption process of unfolded proteins to a solid matrix in the column by introducing the cell lysate containing the above denaturant and the unfolded protein to the top part of the column which has the solid matrix of higher density than the cell debris suspended on the liquid in the equilibrium state; the elimination process of cell lysate except the adsorbed protein by introducing the buffer solution containing the denaturant to the top part of the column; the refolding process of the unfolded protein by the gradual decrease of the denaturant concentration by introducing the buffer solution without the denaturant to the top part of the column; and the obtaining process of the refolded protein from the above column.
