title: A variant of prothrombin induced in cattle by prolonged administration of warfarin.
abstract: Cows on long term Warfarin therapy produce a form of prothrombin which, although it binds to barium citrate, has a low biological activity. Activation experiments on this form of prothrombin show that it is only slowly converted to thrombin in the presence of Ca2+, although the thrombin produced has normal activity. Further experiments show that the Fragment 1 region of the molecule has a reduced calcium binding capacity. The results indicate the existance of a partially carboxylated form of prothrombin.
mesh_terms: D000818:Animals; D001464:Barium / Q000378:metabolism; D001665:Binding Sites; D001780:Blood Coagulation Tests; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002951:Citrates / Q000378:metabolism; D004789:Enzyme Activation; D004950:Esterases / Q000378:metabolism; D005170:Factor X / Q000378:metabolism; D005260:Female; D007118:Immunoassay; D011485:Protein Binding; D011516:Prothrombin / Q000378:metabolism*; D013917:Thrombin / Q000096:biosynthesis; D013997:Time Factors; D014859:Warfarin / Q000494:pharmacology*
chemical_list: D002951:Citrates; D001464:Barium; D014859:Warfarin; D011516:Prothrombin; D005170:Factor X; D004950:Esterases; D013917:Thrombin; D002118:Calcium