1979 Volume 27 Issue 7 Pages 1618-1625
A potent kinin-inactivating enzyme, Shimeji kininase, may have applications in research on the kallikrein-kinin system in the body. In order to test its suitability, the effects of this enzyme, in addition to kinin destruction, on substances related to the kallikrein-kinin system were investigated. This enzyme hardly affected the esterase activities of the glandular kallikreins. It destroyed the heat-denatured kininogens of various species, but did not attack the native rat low molecular weight kininogen molecule. The vasodilative activity of this enzyme assayed in the dog was almost negligible, and no kinin activity could be detected in incubation mixtures of this enzyme and heatdenatured kininogens of various species by the Magnus method. Therefore, this enzyme does not have kininogenase activity, and its destruction of the heat-denatured kininogens was not due to kinin liberation from the kininogens. Intravenous injection of this enzyme in the rat caused the depletion of plasma high molecular weight kininogen, presumably due to plasma prekallikrein activation, while the low molecular weight kininogen level in plasma was not significantly changed.