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Protofibrin clots induced by calcium and zinc
Author(s) -
Marx Gerard
Publication year - 1987
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360260610
Subject(s) - chemistry , divalent , fibrin , thrombin , fibrinogen , calcium , biophysics , zinc , ionic strength , ionic bonding , monomer , crystallography , inorganic chemistry , biochemistry , aqueous solution , ion , organic chemistry , polymer , platelet , immunology , biology
During the course of studies with fibrin protofibrils, produced by adding hirudin to thrombin‐activated fibrinogen prior to the onset of gelation, turbid clots were observed to be generated merely by adding Ca(II) or Zn(II) to protofibrils. The rate of gelation (CT) and turbidity of the “protofibrin” clots increases with cation levels in a concentration‐dependent manner, with Zn(II) much more potent than Ca(II). For example, 50 μ M Zn(II) generated a more turbid protofibrin clot than 0.5 m M Ca(II). In combination, levels of Zn(II) and Ca(II), which individually have no effect, induce protofibril gelation. The generation of protofibrin clots by Zn(II) is decreased at increasing ionic strength. Apparently, the underlying electrostatic forces that bind the monomers in fibrin and protofibrin gels are similar. SEM micrographs show that Ca(II)‐ or Zn(II)‐induced protofibrin clots (600–1500Å thick) are essentially indistinguishable from those formed directly from fibrinogen and thrombin with divalent cation. The protofibrin fibers induced by the cations are thicker than the fibers formed directly from fibrinogen and thrombin in the absence of divalent cation. Branching appears brought about the the divalent cation‐sensitive lateral association of different protofibril strands. These findings describe simple experimental methods for separately studying the early and late stages of fibrin gelation.