Characterization of a potent platelet aggregation inducer from Cerastes cerastes (Egyptian sand viper) venom
| Autor: | M.F. El-Asmar, Gerald Soslau, A.R. Basheer |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Protein Denaturation
Platelet Aggregation Molecular Sequence Data Biophysics Hirudin Disuccinimidyl suberate Viper Venoms Biochemistry chemistry.chemical_compound Thrombin Structural Biology Thrombin receptor medicine Humans Platelet Amino Acid Sequence Amino Acids Molecular Biology Blood Coagulation biology Leupeptin Serine Endopeptidases Cerastes cerastes biology.organism_classification Molecular biology Protein Kinase A Inhibitor Molecular Weight Kinetics chemistry medicine.drug |
| Zdroj: | Biochimica et biophysica acta. 1250(1) |
| ISSN: | 0006-3002 |
| Popis: | A potent, proteinaceous inducer of platelet aggregation designated as IVa, has been purified to homogeneity from Cerastes cerastes venom by molecular sieve and ion exchange chromatography. It is composed of 2 subunits with total M r of 62 000 as shown by native gel chromatography and chemical cross-linking with disuccinimidyl suberate. It is not clear at the present time whether both subunits are identical gene products, however, both have identical N-terminal sequences for the first 15 amino acids. The protein has a p I above 9.6. IVa (0.1 μg/ml) could aggregate platelets up to 80% and was inhibited by p-APMSF, leupeptin, iodoacetamide, protein kinase C inhibitor, phosphatase inhibitor, ATP and PGE 1 , while it was insensitive to acetylsalicylic acid, ADP scavenger system, protein kinase A inhibitor and hirudin. Protein IVa is a serine proteinase with thrombin-like activity as it hydrolysed thrombin chromogenic substrate CBS 34.47, its aggregatory activity was partially inhibited by monoclonal antibodies against GPIb and the thrombin receptor, as was the thrombin, and its ability to induce intracellular Ca 2+ release was blocked by pretreating platelets with thrombin. Unlike thrombin, the IVa protein showed very weak coagulant activity as indicated by plasma recalcification time and fibrinogen clotting time although it could hydrolyse fibrinogen α-chains. |
| Databáze: | OpenAIRE |
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