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[Comparison of the catalytic properties of alpha- and beta-forms of thrombin].Sravnenie kataliticheskikh svoistv alpha- i beta-form trombinaстатья
Дата последнего поиска статьи во внешних источниках: 28 мая 2015 г.
- Авторы: Strukova S.M., Umarova B.A., Kireeva E.G., Kudriashov B.A.
- Журнал: Biochemistry (Moscow)
- Том: 43
- Номер: 4
- Год издания: 1978
- Издательство: Pleiades Publishing, Ltd
- Местоположение издательства: Road Town, United Kingdom
- Первая страница: 708
- Последняя страница: 716
- Аннотация: 18-25-fold purified alpha-thrombin, having high esterase activity and coagulating ability of 2500 NIH u per 1 mg of protein, was isolated using chromatography of commercial thrombin through SP-Sephadex C-50. Limited proteolysis of alpha-thrombin on the column with immobilized trypsin resulted in the appearance of beta-thrombin with alpha-thrombin-like esterase activity and tracing coagulating activity (2-5 NIH u per 1 mg of protein). Molecular weight analysis of alpha- and beta-thrombin forms suggests that a peptide (or peptides) with Mr of 1100 is splitted off under proteolysis. Some similarity is revealed in kinetic parameters (Km(app) and kkat) of TAME and BAME hydrolysis by alpha- and beta-thrombin, although Km(app) is somewhat low (approximately 2-fold) for alpha-thrombin. Investigation of TAME hydrolysis kinetics by both thrombin forms at a wide range of substrate concentrations has revealed the effect of substrate activation. Kinetic constants Ks and beta for high substrate concentrations are calculated. It is suggested that the similarity of alpha- and beta-thrombin action on arginine esters and sharp differences in their effect on fibrinogen may be a result of a disturbance of substrate-binding region of beta-thrombin active site.
- Добавил в систему: Струкова Светлана Михайловна