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Biomedical subjects

R Machovich

Publications and source records attributed to R Machovich.

At least 91 records · Page 5Linked to original sources
PubMed1975

Mechanism of action of heparin through thrombin on blood coagulation.

It has been suggested that heparin can affect blood coagulation through thrombin, i.e. the binding of heparin to thrombin induces a conformational change in the enzyme, facilitating a complex formation between thrombin and antithrombin (Machovich, T., Blaskó, Gy. and Pálos, L. (1975) Biochim. Biophys. Acta 379, 193-200). This hypothesis seems to have been proved. Modification of arginine residues in thrombin did not result in decreased thrombin activity and decreased sensitivity to antithrombin, whereas the heparin sensitivity of the enzyme and the thrombin-antithrombin reaction were diminished.

Antithrombins↗
PubMed1975

Heparin-sensitive and nonsensitive forms of thrombin.

Two forms of thrombin (Ts-thrombin and Tp-thrombin) were found with respect to heparin sensitivity. Inactivation of Ts-thrombin by antithrombin-III was facilitated with heparin, whereas inactivation of Tp-thrombin was not. Both thrombins were bound to heparin in a Sephadex G-200 gel filtration experiment. Ts-thrombin proved to be more stable and was better protected by heparin against heat inactivation of 54 degrees C than Tp-thrombin.

Animals↗
PubMed1975

Action of heparin on thrombin-antithrombin reaction.

Thrombin partially purified from bovine plasma can be inactivated at 60 degress C. In the presence of 10 units of heparin the extent of inactivation decreases. When thrombin and heparin are mixed and incubated for 5 min at 0 degrees C before gel filtration on Sephadex G-200, thrombin with heparin is eluted prior to either thrombin or heparin laone. These data suggest a complex formation between thrombin and heparin. Immobilized heparin binds thrombin. The enzyme can be eluted with 0.05 M Tris-HCl buffer, pH 7.3, containing an ion mixture of Na+, K+ and Ca2+ at 73, 3 and 11 mM, respectively, at 0 degrees C and with 0.05 M Tris-HCl buffer, pH 7.3, containing 0.5 M NaCl at 20 degrees C. During the same chromatographic procedure, antithrombin-III (heparin cofactor) partially purified from human plasma is eluted with 0.05 M Tris-HCl buffer, pH 7.3, at 0 degrees C as well as 20 degrees C. Although, as described in the literature, heparin binds to antithrombin, our findings suggest another possibility, i.e. that the binding of heparin to thrombin induces a conformational change in the enzyme facilitating a complex formation between thrombin and antithrombin-III.

Antithrombin III↗