The nature of platelet @entity5582 was elucidated by comparison of @entity556 binding and @entity5582 activities of intact platelets and by purification of @entity5582 from platelet lysates using glycerol osmotic lysis, @entity1068 precipitation and Sephadex gel filtration techniques. The major portion of the @entity5582 and @entity556 binding activity of intact platelets is lost after brief sonication. The @entity5582 activity in destroyed platelets is found to be due to platelet fibrinogen. Treatment of platelets with @entity5015 (100 microng/ml) markedly inhibits (greater than 80%) the release of platelet fibrinogen induced by @entity556 . However, the @entity5015 treatment produced slight (less than 30%) but significant decrease of @entity5582 activity of intact platelets, whereas the binding of @entity556 to platelets was not affected by @entity5015 treatment. The amounts of @entity556 bound to and inactivated by @entity5015 -treated platelets at the same cell concentration are identical. The above results suggest that platelets contain at least two @entity5582 activities. One, which accounts for the major portion of platelet @entity5582 is mediated by @entity556 binding to platelets. The other, which attributes to a lesser extent to platelet @entity5582 activity, is due to the release of platelet fibrinogen. Also, @entity5582 is readily demonstrated in a plasma medium indicating physiological significance of platelet @entity5582 .

Platelet antithrombins: role of XXXX binding and the release of platelet fibrinogen.

@entity5015 :: ('MESH:D000527', 'Chemical') :: ['PGE1'] @entity5582 :: ('462', 'Gene') :: ['antithrombin'] @entity1068 :: ('MESH:D000431', 'Chemical') :: ['ethanol'] @entity556 :: ('2147', 'Gene') :: ['thrombin']
@entity556 :: (2147,Gene) :: ['thrombin']
