Purification of inactive kallikrein from rat urine

An inactive kallikrein was purified from rat urine, and some of the properties of this enzyme were examined, in comparison with those of rat urinary kallikrein (RUK). The purified inactive kallikrein reacted with the antiserum against RUK and migrated slightly more slowly than RUK, on the immunoelectrophoresis. The molecular weights of the inactive kallikrein and RUK were estimated to be 44,000 and 38,000 by gel filtration, respectively. These results indicate that the rat urinary inactive kallikrein is immunologically identical with RUK, but this inactive enzyme has biochemical properties different from those of RUK, with respect to molecular weight and electrophoretical mobility.