Native plasma kallikrein is cleared at similar rates by mammalian and avian livers.

Rat plasma kallikrein (RPK) is a serine protease that circulates as an inactive precursor, prokallikrein, and once activated is efficiently cleared by the liver by a carbohydrate-dependent, Ca(2+)-independent mechanism. Seven hepatic lectin systems have been described for mammals but not all of these animal lectins are expressed in the avian liver. Using a liver perfusion system we compared the plasma kallikrein clearance of rats (N = 10) and pigeons (N = 4). Our results show that the lectin responsible for the hepatic clearance of plasma kallikrein is also present in pigeon liver and that this organ clears the enzyme with an efficiency (11.4 +/- 1.3 pmol/g, 20 min) similar to that of the rat liver (10.0 +/- 0.7 pmol/g, 20 min).