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Divalent cations induce protofibril gelation
Author(s) -
Marx Gerard
Publication year - 1988
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830270207
Subject(s) - divalent , fibrin , chemistry , monomer , coagulation , biophysics , polymerization , fiber , calcium , turbidity , magnesium , crystallography , polymer , organic chemistry , psychology , oceanography , psychiatry , immunology , biology , geology
Soluble fibrin oligomers (protofibrils) undergo phase change merely by adding 1–2 mM Ca 2+ 25‐100 μM Zn 2+ . The cation‐induced “protofibrin” clots appear similar to normally formed fibrin gels. Maximal clot turbidity of protofibrin gels increases with cations in a concentration‐dependent manner. Magnesium (less than 0.5 mM) is ineffective in inducing protofibril gelation. Turbidity and degree of polymerization (DP) [indirectly expressed as AT (activation time)] appear to be positively correlated, regardless of whether the divalent cation is Ca 2+ or Zn 2+ . Cross sections of Ca 2+ ‐induced protofibrin fibers are ∼6–18‐fibrin‐monomers‐thick. With both Ca 2+ and 40 μM Zn 2+ , fiber cross section increases to 30–50 monomers thick. Negatively stained Zn 2+ ,‐ and Ca 2+ ‐induced protofibrin gels exhibit banding periodicity of ∼ 240 Å, similar to that of normally generated fibrin gels. Regions of lateral merging of individual segments of the protofibrin leads to increased cross section of the fiber and forms a branch required for gelation. These findings indicate that the rate of coagulation and the ultimate thickness of the fibers both relate to lateral associative processes of protofibrils, which are augmented by physiologic concentrations of 2+ and Zn 2+ .