[Contact activation of prekallikrein and plasminogen in plasma]. / Kontaktnaia aktivatsiia prekallikreina i plazminogena v plazme krovi.

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 . HCl, kininogen and protamine sulphate formed by kallikrein. The data permit supposing that optimal activation of the Hageman factor requires the polar (but not ionic) groups with hydrophilic properties on activating surfaces. Plasminogen under contact activation, in contrast to prekallikrein is activated only in the diluted plasma (pH 4.8), and not completely. Possible mechanisms of the contact activation and interaction of the Hageman factor, prekallikrein and high-molecular kininogen in this process are discussed.

[Plasmin in human blood plasma]. / Oss;edpvamoe 1/4;az,oma v Plazme krovi cheloveka.

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.

[Proteolytic enzymes in palatine tonsil lymphocytes]. / Issledovanie proteoliticheskikh fermentov v limfotsitakh nebnykh mindalin

Homogenates and subcellular lymphycyte fractions of human tonsilla palatina contained proteolytic enzymes operating in slightly acidic (pH 3.6) and slightly alkaline (pH 7.5) media. The enzymes hydrolyzed proteins (hemoglobin, protamine sulphate, kininogen) and syntheitc substrates (N-benz-d,1-arg-p-nitroanilide, N-benz-1-arg ethyl ester, hippuryl-1-lys and bradikinin). Data on localization of the proteolytic enzymes in subcellular lymphocyte fractions of human tonsilla were obtained.