[Thrombin and anticoagulant therapy].

New data which reveal rational approaches for pharmacologic control of blood coagulation process and confirm the key role of thrombin in haemostasis processes compared with other proteinases are presented in the review. Modulation of thrombin properties described in the review gives a new possibility for creating anti-thrombin preparations. Thrombin allosteria can serve a basis for development of new therapy.

[Sodium ions as the effector of catalytic action of alpha-thrombin].

A process of thrombin interaction with synthetic and natural substrates in the presence of Na+ ions has been analyzed in the survey. Molecular bases of this interaction have been presented, interrelation between the structure and function of thrombin has been noted; the nature of the unique site of its active centre which determines high thrombin affinity for the substrates and increase of its catalytic activity defined by the term of "specificity to univalent cations" have been considered in detail. Na+ ions play the role of allosteric effector in realization of two informational states of thrombin which penform, respectively, two fundamental and competing functions in the process of hemostasis.

[Human thrombin: drug stability and stabilization].

Stabilization of enzymes is a key factor when using biocatalysis in practice. Each enzyme stability depends both on the structure of its molecule and on the effect of various environmental factors, thus, one of the methods of the enzyme stability preservation is the formation of optimal macromedium. Thus, water structure and enzyme hydration change in the presence of solvable additives that affects its stability and catalytic properties.

[Interrelation between thrombin structure and its stability].

Temperature inactivation of human thrombin has been studied when finding out the mechanism of this enzyme stabilization by amino acids. Effect of a number of amino acids on thrombin in the conditions (pH) of the highest activity of proteinase has been investigated. It is established that most amino acids are characterized to more or less extent by the protective action, when hampering the temperature inactivation of the enzyme.

[Interaction of human alpha-thrombin with organic ligands of ionic nature].

Investigations results of human thrombin interaction with organic ligands of ion nature containing nonpolar groups are presented. It is shown that electrostatic interaction is the basic one under enzyme binding, while hydrophobic binding is only additional function in the reaction enzyme-ligand, this fact is confirmed by the absence of interaction between thrombin and rivanol which has a positive charge side by side with cumbrous hydrophobic group. New data are presented about the ligand specificity of binding sites of thrombin active centre.