Effects of t-AMCHA and EACA on the plasma kallikrein system.

Varied amounts of t-AMCHA or EACA added to non-contact fresh dog plasma generates kininogenase and TAME esterase activities. These phenomena may be abolished by prior addition of lima bean trypsin inhibitor. t-AMCHA or EACA had no effect on partially purified kallikrein, but had a significant inhibitory influence on plasma kininase. The generation of prekallikrein activator with t-AMCHA was ascertained by gel filtration on a Sephadex G-100 column. The blood kinin level increased about 50% one hr after administration of t-AMCHA. It is suggested from these results that t-AMCHA may initiate the true activation of the kallikrein system by activating the Hageman factor.