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P Wiltzius

Publications and source records attributed to P Wiltzius.

27 records · Page 2Linked to original sources
PubMed1982

Fibrin aggregation before sol-gel transition.

Fibrinogen solutions (concentrations 2 mg/ml, 0.15-M Tris-NaCl buffer, pH 7.4) were incubated at 20 degrees C with quantities of reptilase or thrombin that were so small that the polymerization process could be followed for several hours by means of static and dynamic light scattering. The scattered intensity and its correlation function were recorded at scattering angles between 30 degrees and 150 degrees. The measured data were compared with model calculations based on the Flory-Stockmayer distribution, which predicts a sol-gel phase transition. This distribution is characterized by a parameter, lambda, that indicates the extent of aggregation. lambda = 0 corresponds to the monomeric solution, and lambda = 1 indicates the sol-gel transition. Good agreement was found for monomeric units of 75-nm length aggregating (a) end-to-end in the early stage (0 less than or equal to lambda less than or equal to 0.3), and (b) in a staggered overlap pattern for the progressing polymerization (0.3 less than or equal to lambda less than 1). Before the gel point was reached, no systemic difference was observed between the data obtained after activation with thrombin which releases both fibrinopeptides A and B from fibrinogen, and reptilase, which exclusively releases the fibrinopeptides A. This confirms that the release of the fibrinopeptides A is the essential prerequisite for the aggregation process.

Batroxobin↗
PubMed1979

[The shape of fibrin-monomer molecules in solution].

Human fibrin monomers after thrombin and reptilase proteolysis can be kept in solution at pH 4.6. Using dynamic light scattering, the hydrodynamic data of these two monomer solutions and of fibrinogen in the same buffer were compared to fibrinogen at pH 7.4. The translational diffusion coefficient DT20W of fibrinogen at pH 7.4 was 1.95 +/- 3% 10(-7).cm2.sec-1 and the rotational diffusion coefficient DR20,W 50,000 +/- 30%.sec-1. The corresponding DT and DR for the two monomer solutions and fibrinogen at pH 4.6 did not significantly deviate from the above values. It is concluded that enzymatic proteolysis of fibrinogen, triggering release of the aminoterminal fibrinopeptides A and B, does not produce a major conformational change in the resulting monomers.

Fibrin↗