Bacitracin and gramicidin s as biospecific ligands during affinity chromatography of human thrombin
Gaida, A.V.; Magerovskii, Y.V.; Monastyrskii, V.A.
Biokhimiya 52(4): 569-576
It was shown that the cyclic polypeptide antibiotic bacitracin is a competitive inhibitor of fibrinogen clotting by thrombin. Biospecific adsorbents for isolation of thrombin by gramicidin S and bacitracin attachment to silochrome S-80 modified by .gamma.-glycidooxypropyl groups were synthesized. The thrombin yield at pH 7.2 and 8.0 was 76.5-96%, purification-6.2-11.6-fold, specific coagulating activity-940-1750 NIH u/mg protein. At pH 6.1 the enzyme does not practically bind to the adsorbents. In all probability, the differences in thrombin binding are due to conformational changes in the enzyme molecule, when pH changes from 6.1 to 7.2. Possible application of the synthesized adsorbents for obtaining laboratory and commercial preparations of thrombin and their perspective use for purification of other blood plasma serine proteinases possessing a narrow specificity are discussed.