[Contact activation of prekallikrein and plasminogen in plasma].

Activation of the Hageman factor-prekallikrein system in the whole human blood plasma is studied as affected by organic silica (aerosils) with anionic and cationic properties. Positive- and negative-charged aerosils are shown to possess the same ability to activate prekallikrein. Activity of prekallikrein was manifested in hydrolysis of the chromogenic substrate--Benz-Pro-Phen-Arg-paranitroanilide .

[Plasmin in human blood plasma].

Formation of plasmin was studied when treating the human diluted blood plasma with kaolin in acid medium. The activity of the formed enzyme was determined quantitatively from the splitting of protamin sulphate, fibrin and fibrinogen. Dependence of plasminogen activation on time of plasma incubation with kaolin and on temperature as well as the effect of proteinases inhibitors on the plasmin activity are studied.