Activation of dog plasma kininogenase with glass

The activity of glass-activated kallikreins in dog plasma was determined by measuring both kininogenase and p-toluensulphonyl-l-arginine methyl ester (TAME) esterase activities. Non-contact plasma, after being shaken with glass beads, was centrifuged immediately at 4° to sediment the glass beads and the supernatant was used for the experiments. Glass activation of dog plasma was more effective on TAME esterase activity. When the supernatant alone was preincubated at 37°, its kininogenase activity was suppressed about 50 per cent, while TAME esterase activity was unchanged. High kininogenase activity in the supernatant could be induced by treatment with 50% ammonium sulphate, suggesting the presence of peculiar inhibitors for kininogenase activity in glass-activated dog plasma. Kininogenase inhibitors in plasma were separated by gel filtration on Sephadex G-200; there were two inhibitors which were able to suppress kininogenase activity in glass-activated dog plasma. When dog plasma was preincubated with lima bean trypsin inhibitor, generation of both kininogenase and TAME esterase was significantly suppressed during contact with glass beads. Acetone-activated dog plasma could be reactivated by glass contact, although the level of kininogenase activity was lower than that by glass activation alone. The non-absorbed supernatant of glass-activated dog plasma formed kinins from rat kininogen. The present results suggest that the kinin-forming system by glass activation in dog plasma is not qualitatively different from that in human plasma with the exception of the presence of potent kininogenase inhibitors in the plasma.