Relationship of final thickness of fibrin fibers to maximal rate of assembly and to fibrinopeptide B release

Pirkle, Hubert; Vukasin, P.; Theodor, Ida; Miyada, D. S.

doi:10.1515/9783110871951-010

Cited by 3 publications

(6 citation statements)

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“…Experimental curves for thrombin cleavage are illustrated in Fig. 4; the turbidity curves for different concentrations of batroxobin, which specifically cleaves the A fibrinopeptides, were also measured (data not shown), and, as demonstrated by others (e.g., Shen, et al, 1977;Carr, et al, 1985;Pirkle, et al, 1986), they are qualitatively similar to those for thrombin and can be fit by the kinetic model here. Both experimental and model Modeling the Kinetics of Fibrin Assembly data show that at low enzyme concentrations, or slow rates ofcleavage, the maximum rate ofgrowth offibers is slow and the maximum turbidity or fiber size is large.…”

Section: Discussionsupporting

confidence: 73%

“…Aspects of the experimental curves resulting from different enzyme concentrations have been studied. Plots of maximum turbidity versus maximum rate of turbidity change are linear (Pirkle, et al, 1986); plots derived from the calculated curves are similar. Results from some abnormal fibrinogens where the rate of cleavage of the A fibrinopeptides is affected may also be accounted for by this model.…”

Section: Discussionmentioning

confidence: 72%

“…Such changes in lateral aggregation would be expected considering the measured increase in calcium binding accompanying fibrinopeptide B cleavage (Mihalyi, 1988). For example, cleavage of fibrinopeptide B, like an increase in kfg, can result in a decrease in the lag period, an increase in the maximum rate ofturbidity development and an increase in the maximum turbidity (Shen, et al, 1977;Pirkle, et al, 1986). Likewise, larger fiber bundles are observed by electron microscopy upon cleavage of fibrinopeptide B (Weisel, 1986b;Mosesson, et al, 1987).…”

Section: Discussionmentioning

confidence: 94%

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Computer modeling of fibrin polymerization kinetics correlated with electron microscope and turbidity observations: clot structure and assembly are kinetically controlled

Weisel

Nagaswami

1992

Biophysical Journal

328

350

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Although much is known about fibrin polymerization, because it is complex, the effects of various modifications are not intuitively obvious and many experimental observations remain unexplained. A kinetic model presented here that is based on information about mechanisms of assembly accounts for most experimental observations and allows hypotheses about the effects of various factors to be tested. Differential equations describing the kinetics of polymerization were written and then solved numerically. The results have been related to turbidity profiles and electron microscope observations. The concentrations of intermediates in fibrin polymerization, and fiber diameters, fiber and protofibril lengths have been calculated from these models. The simplest model considered has three steps; fibrinopeptide A cleavage, protofibril formation, and lateral aggregation of protofibrils to form fibers. The average number of protofibrils per fiber, which is directly related to turbidity, can be calculated and plotted as a function of time. The lag period observed in turbidity profiles cannot be accurately simulated by such a model, but can be simulated by modifying the model such that oligomers must reach a minimum length before they aggregate. Many observations, reported here and elsewhere, can be accounted for by this model; the basic model may be modified to account for other experimental observations. Modeling predicts effects of changes in the rate of fibrinopeptide cleavage consistent with electron microscope and turbidity observations. Changes only in the rate constants for initiation of fiber growth or for addition of protofibrils to fibers are sufficient to account for a wide variety of other observations, e.g., the effects of ionic strength or fibrinopeptide B removal or thrombospondin. The effects of lateral aggregation of fibers has also been modeled: such behavior has been observed in turbidity curves and electron micrographs of clots formed in the presence of platelet factor 4. Thus, many aspects of clot structure and factors that influence structure are directly related to the rates of these steps of polymerization, even though these effects are often not obvious. Thus, to a large extent, clot structure is kinetically determined.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 94%

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Computer modeling of fibrin polymerization kinetics correlated with electron microscope and turbidity observations: clot structure and assembly are kinetically controlled

Weisel

Nagaswami

1992

Biophysical Journal

328

350

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“…Comparison to Other Snake Venom Thrombin-like Enzymes. Several thrombin-like enzymes were isolated from the venoms of Agkistrodon rhodostroma (Hatton, 1973;Nolan et al, 1976), C. adamanteus (Markland & Damus, 1971;Markland, 1976), Bothrops atrox (Holleman & Weiss, 1976;Stocker & Barlow, 1976), and Bitis gabonica (Niljoen et al, 1979;Pirkle et al, 1986). Although the molecular weights are roughly similar (31 400-40 000), there are many differences in other properties such as isoelectric point and enzyme activities on various blood clotting factors.…”

Section: Discussionmentioning

confidence: 99%

“…Thrombin-like enzymes are widely distributed in venoms of the Crotalidae family (Gaffney, 1977); however, they are found in the snake venoms of a few other families (Bajwa et al, 1982). The well-known thrombin-like enzymes are Arvin (ancrod), batroxabin, reptilase, gabonase, crotalase, and many others (Markland & Damus, 1971;Hessel & Blomback, 1971; Pirkle et al, 1986;Itoh et al, 1987).…”

mentioning

confidence: 99%

Characterization of cerastobin, a thrombin-like enzyme from the venom of Cerastes vipera (Sahara sand viper)

Tm¹,

At²,

Mf³

1989

Biochemistry

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Cerastobin, a thrombin-like enzyme, was isolated from the venom of Cerastes vipera (Sahara sand viper) in homogeneous form. Cerastobin had a molecular weight of 38,000 with 348 amino acid residues. It had an isoelectric point of 7.7 (a pH optimum of 7.9 and a temperature optimum of 45 degrees C). Cerastobin hydrolyzed arginine-containing synthetic substrates such as TAME, BAME, and BAEE, but BAPNA was not hydrolyzed. Cerastobin had thrombin-like activity, producing fibrin from fibrinogen and also hydrolyzing chromogenic substrates for thrombin such as 2AcOH.H-D-CHG-But-Arg-pNA (CBS 34.47) and H-D-Phe-Pip-Arg-pNA (S-2238). It showed kallikrein-like activity and hydrolyzed kallikrein substrates 2AcOH.H-D-Phe-Gly-Arg-pNA (CBS 33.27) and H-D-Pro-Phe-Arg-pNA (S-2302). It produced bradykinin from bradykininogen, as uterus contraction was observed. A serine inhibitor, DFP, exerted a pronounced inhibitory effect, suggesting that cerastobin is a serine-type protease. The sequence of 37 residues from the amino-terminal end was investigated. The amino-terminal amino acid was valine as it is in most other thrombin-like enzymes. The amino acid sequence of cerastobin was similar to that of thrombin in some residues and had some homology with that of kallikrein. However, cerastobin showed a high degree of homology to thrombin-like enzymes isolated from various snake venoms. Factor X was partially degraded by cerastobin. It was also found that antithrombin III was degraded by the enzyme. The alpha and beta chains of fibrin monomer were preferentially hydrolyzed by cerastobin, but the gamma chain was quite resistant.

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The effect of “aging” of fibrinogen molecule on the structure and properties of fibrin gel

Rozenfel'd

Leonova

Biryukova

2007

Biol Bull Russ Acad Sci

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Relationship of final thickness of fibrin fibers to maximal rate of assembly and to fibrinopeptide B release

Cited by 3 publications

References 0 publications

Computer modeling of fibrin polymerization kinetics correlated with electron microscope and turbidity observations: clot structure and assembly are kinetically controlled

Computer modeling of fibrin polymerization kinetics correlated with electron microscope and turbidity observations: clot structure and assembly are kinetically controlled

Characterization of cerastobin, a thrombin-like enzyme from the venom of Cerastes vipera (Sahara sand viper)

The effect of “aging” of fibrinogen molecule on the structure and properties of fibrin gel

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