ABSTRACT
Chemical modification of surface amino groups of bovine testicular hyaluronidase with aldehyde dextran was conducted. It was found that with the increase of modification degree of hyaluronidase amino groups the value of residual enzymatic catalytic activity is decreased rather monotonously. It turned out that the value of inhibition of enzyme activity by heparin considerably depends on modification degree of enzyme. This dependence is of a threshold character. Sharp conformational changes in the enzyme occurring at 70-90% degree of its modification considerably lowers heparin inhibition. The higher the degree of hyaluronidase modification, the weaker its inhibition by heparin. More completely/deeply modified derivatives of hyaluronidase (modification degree 96-100%) are practically not inhibited by heparin. Thus, chemical conjugation of hyaluronidase with aldehyde dextran regulates the value of enzyme inhibition by heparin. Hyaluronidase modification becomes an informative tool to study the mechanism of inhibition of its enzyme activity and an efficient means for the development of new therapeutic preparations improving tissue permeability during cardiovascular injuries.
Subject(s)
Enzyme Inhibitors/pharmacology , Heparin/pharmacology , Hyaluronoglucosaminidase/antagonists & inhibitors , Animals , Anticoagulants/pharmacology , Cattle , Dextrans/chemistry , Enzyme Stability , Hyaluronoglucosaminidase/chemistry , Hyaluronoglucosaminidase/metabolism , Male , Protein Conformation , Testis/enzymologyABSTRACT
The modification of hyaluronidase by aldehydodextran regulates inhibition of the enzyme by heparin. A 70-90% modification of the surface amino groups of hyaluronidase results in sharp conformational changes and a substantial decrease of its inhibition by heparin, whereas hyaluronidase derivatives with a modification degree of 96-100% are practically uninhibited.
Subject(s)
Fibrinolytic Agents/metabolism , Heparin/metabolism , Hyaluronoglucosaminidase/chemistry , Hyaluronoglucosaminidase/metabolism , Dextrans , Enzyme Activation , Fibrinolytic Agents/pharmacology , Heparin/pharmacology , Humans , Hyaluronoglucosaminidase/antagonists & inhibitors , Structure-Activity RelationshipSubject(s)
Tissue Plasminogen Activator/chemistry , Urokinase-Type Plasminogen Activator/chemistry , Animals , Dogs , Infusions, Intravenous , Metabolic Clearance Rate , Recombinant Proteins , Structure-Activity Relationship , Thrombophlebitis/drug therapy , Tissue Plasminogen Activator/pharmacokinetics , Urokinase-Type Plasminogen Activator/pharmacokineticsABSTRACT
Conjunctive administration of the tissue-type plasminogen activator (t-PA) and the urokinase-fibrinogen covalent conjugate (UK-Fbg) was studied by the example of venous thrombosis in dogs. Comparing the effect of separate use of the two components, we observed the potentiation of thrombolytic effect induced by an i.v. bolus infusion administration of the tissue-type plasminogen activator (1 and 4 mg, respectively) combined with a bolus administration 15 min after the first injection of the 25,000 IU UK-Fbg. Faster-action and potentiation effects of thrombolysis were observed with the same administration scheme when the t-PA was used as bolus infusion (1 and 1 mg, respectively) combined with a bolus of the 250,000 IU fibrinogen-modified urokinase. The findings indicate an approach to the development of efficient thrombolytic compositions.
