Fibrinopeptide B and Aggregation of Fibrinogen
| العنوان: | Fibrinopeptide B and Aggregation of Fibrinogen |
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| المؤلفون: | John R. Shainoff, Beatriz N. Dardik |
| المصدر: | Science. 204:200-202 |
| بيانات النشر: | American Association for the Advancement of Science (AAAS), 1979. |
| سنة النشر: | 1979 |
| مصطلحات موضوعية: | Fibrinopeptide B, Fibrinogen, Turn (biochemistry), Crotalid Venoms, medicine, Humans, Fibrinopeptide, Amino Acid Sequence, Fibrinolysin, Binding site, Fibrinopeptide A, chemistry.chemical_classification, Binding Sites, Multidisciplinary, Chemistry, Temperature, Copperhead, Molecular Weight, Enzyme, Coagulation, Biochemistry, Snake venom, comic_books, Biophysics, comic_books.character, Protein Binding, medicine.drug |
| الوصف: | Copperhead venom procoagulant enzyme, previously shown to remove fibrinopeptide B at faster rate than fibrinopeptide A, has been found to release little of the A peptide at temperatures below 14°. At low temperatures, tight aggregation of the derivative lacking B blocked release of A by the enzyme. Transient release of A occurred, but stopped as removal of B approached completion. Overall losses of A amounted to 8% and 2% from human and rabbit fibrinogen respectively. Resultant clots with A intact dissolved on warming to 37°, whereafter release of A resumed with secondary coagulation ensuing. When dissolved at 37° with PMSF-inactivated enzyme, the fibrin remained highly soluble (>12 mg/ml). Ultracentrifugation showed constant levels of 8S monomer together with 16S aggregates in amounts accounting for the total protein at concentrations down to 0.16 mg/ml, and monomer alone at lower concentrations. From changes in saturation level of monomer at lower temperatures, the enthalpy of aggregation appeared to be about half of the -50 kcal/mole associated with aggregation of regular fibrin. Other experiments indicate that removal of the A and B peptides unmasks separate aggregation sites, each of which place the monomers in alignment suitable for rapid crosslinking. The β-chain segment spanning residues 15-42 appears to be critically involved in the aggregation that follows release of B itself, because the aggregation does not occur when this segment is removed together with B in early stages of reaction between fibrinogen and plasmin. The aggregation which follows release of A depends on a different site, because the early alterations inflicted by plasmin do not prevent coagulation of fibrinogen by thrombin. (Supported in part by USPHS Grant HL-16361). |
| تدمد: | 1095-9203 0036-8075 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f43d8c1c160c33df323c9fa959ae2b74Test https://doi.org/10.1126/science.155308Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....f43d8c1c160c33df323c9fa959ae2b74 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 10959203 00368075 |
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