Cleaning experiments were performed by feeding protease solutions as cleaning agents into a packed column of stainless steel particles fouled with beta-lactoglobulin or gelatin. By evaluating the initial desorption rate constants (Brst-order rate constants) and residual amounts of protein, the cleaning efficiencies of the proteases were compared. The initial desorption rate constant depended on the kind of protease used and also on the type of protein to be removed. It increased with protease concentration and reached a constant value at a limit concentration. Kinetic analysis of the proteolytic reactions catalyzed by the proteases revealed that protease with a large Vm(ax)/EKm value for the proteolytic reaction resulted in a large value of the initial desorption rate constant in the enzymatic cleaning at a low protease concentration. The K-m value affected the limit concentration of protease yielding a saturation of initial desorption rate constant.