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Antithrombin action of phosvitin and other phosphate‐containing polyanions is mediated by heparin cofactor II
Author(s) -
Church Frank C.,
Pratt Charlotte W.,
Treanor Rita E.,
Whinna Herbert C.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80164-9
Subject(s) - heparin cofactor ii , thrombin , phosvitin , chemistry , antithrombin , biochemistry , heparin , enzyme , biology , platelet , protein kinase a , immunology
We have examined the antithrombin effects of various phosphate‐containing polyanions (including linear polyphosphates, polynucleotides and the phosphoserine glycoprotein, phosvitin) on the glycosaminoglycan‐binding plasma proteinase inhibitors, antithrombin III (ATIII) and heparin cofactor II (HCII). These phosphate‐containing polyanions accelerate the HCII‐thrombin reaction, as much as 1600‐fold in the case of phosvitin. The HCII‐thrombin reaction with both phosvitin and polynucleotides appears to follow the ternary complex mechanism. The HCII‐thrombin complex is rapidly formed in the presence of these phosphate polyanions (each at 10 μg/ml) when 125 I‐labeled thrombin is incubated with human plasma (ex vivo). None of these phosphate polyanions accelerate the ATIII‐thrombin reaction. Our results suggest that the antithrombotic effect of these phosphate‐containing polyanions is mediated by HCII activation and not by ATIII.