Analysis of the Complex Formation of Heparin with Protamine by Light Scattering and Analytical Ultracentrifugation: Implications for Blood Coagulation Management

2011 ◽  
Vol 133 (4) ◽  
pp. 1134-1140 ◽  
Author(s):  
Jürgen Maurer ◽  
Stephanie Haselbach ◽  
Oliver Klein ◽  
Doan Baykut ◽  
Vitali Vogel ◽  
...  
Keyword(s):  
Light Scattering ◽  
Complex Formation ◽  
Blood Coagulation ◽  
Analytical Ultracentrifugation ◽  
Coagulation Management

scholarly journals The mechanism of assembly of Acanthamoeba myosin-II minifilaments: minifilaments assemble by three successive dimerization steps.

1989 ◽  
Vol 109 (4) ◽  
pp. 1537-1547 ◽  
Author(s):  
J H Sinard ◽  
W F Stafford ◽  
T D Pollard
Keyword(s):  
Electron Microscopy ◽  
Light Scattering ◽  
Ionic Strength ◽  
Analytical Ultracentrifugation ◽  
Myosin Ii ◽  
Alkaline Ph ◽  
Predominant Species ◽  
Assembly Mechanism ◽  
Rapid Equilibrium ◽  
Low Ionic Strength

We used 90 degrees light scattering, analytical ultracentrifugation, and electron microscopy to deduce that Acanthamoeba myosin-II minifilaments, composed of eight molecules each, assemble by a novel mechanism consisting of three successive dimerization steps rather than by the addition of monomers or parallel dimers to a nucleus. Above 200 mM KCl, Acanthamoeba myosin-II is monomeric. At low ionic strength (less than 100 mM KCl), myosin-II polymerizes into bipolar minifilaments. Between 100 and 200 mM KCl, plots of light scattering vs. myosin concentration all extrapolate to the origin but have slopes which decrease with increasing KCl. This indicates that structures intermediate in size between monomers and full length minifilaments are formed, and that the critical concentrations for assembly of these structures is very low. Analytical ultracentrifugation has confirmed that intermediate structures exist at these salt concentrations, and that they are in rapid equilibrium with each other. We believe these structures represent assembly intermediates and have used equilibrium analytical ultracentrifugation and electron microscopy to identify them. Polymerization begins with the formation of antiparallel dimers, with the two tails overlapping by approximately 15 nm. Two antiparallel dimers then associated with a 15-nm stagger to form an antiparallel tetramer. Finally, two tetramers associate with a 30-nm stagger to form the completed minifilament. At very low ionic strengths, the last step in the assembly mechanism is largely reversed and antiparallel tetramers are the predominant species. Alkaline pH, which can also induce minifilament disassembly, produces the same assembly intermediates as are found for salt induced disassembly.

Identification Of The Procoagulant Species In Ellagic Acid Solutions

1981 ◽  
Author(s):  
Paul E Bock ◽  
Joseph D Shore
Keyword(s):  
New Species ◽  
Light Scattering ◽  
Blood Coagulation ◽  
Ellagic Acid ◽  
Spectral Properties ◽  
Metal Ion ◽  
Factor Xii ◽  
Acid Solutions ◽  
Absorbance Spectrum ◽  
Spectral Changes

The species of ellagic acid responsible for initiating intrinsic blood coagulation has been characterized. Ellagic acid is soluble ata level of 30 ± 10 μM in pH 7.4 Tris-saline buffer at 22°C. Dilution of soluble ellagic acid resulted in enhanced plasma procoagulant and kallikrein generating activity, and the appearance of a new absorbance spectrum. These effects were prevented by 1 mi4 EDTA, and the new species could be removed by centrifugation. Addition of stoichiometric Cu2+ to Millipore-filtered soluble ellagic acid generated an absorbance spectrum similar to that caused by dilution in the absence of EDTA, as well as procoagulant and kallikrein activities. Zn2+ and Co2+ caused similar spectral changes and prekail ikrein activation. Although no turbidity was visible and the spectral properties did not indicate extensive light scattering, centrifugation resulted in loss of the absorbance spectrum and activity. We conclude that the procoagulant activity of ellagic acid solutions can be ascribed to slowly settling insoluble aggregates of ellagic acid-metal ion complexes, which are formed with adventitious metal ions present in the diluting buffer. Formation of these aggregates could be prevented but not reversed by 1 mM EDTA. Although soluble ellagic acid may bind to Factor XII, it does not initiate blood coagulation or prekallikrein activation, since these activities were only associated with the insoluble species.

scholarly journals Size and Shape of Human Fibrinogen in Solution

1977 ◽  
Author(s):  
V. Hofmann ◽  
P.W. Straub ◽  
T. Binkert ◽  
E. Serrallach ◽  
W. Känzig ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Analytical Ultracentrifugation ◽  
Rotational Diffusion ◽  
Axial Ratio ◽  
Major Axis ◽  
Fluorescence Depolarization ◽  
Human Fibrinogen ◽  
Size And Shape ◽  
Rotational Diffusion Coefficients

In order to obtain information on size and shape of the fibrinogen molecule in solution the translational diffusion coefficient (DT), the rotational diffusion coefficients (DR⊥ and DR//) and the sedimentation coefficients (S) have been measured on human fibrinogen with a clottaoility above 95%. The methods used were dynamic light scattering, nanosecond fluorescence depolarization and analytical ultracentrifugation. Dynamic light scattering yields DT = 2.0 ± 3% x 10-7 cm2sec–1 at a concentration of 7 mg/ml in 0.15 M Tris-NaCl, pH 7.4. DT is strongly dependent on concentration, being 3.4 ± 10% × 10-7 cm2 sec-1 at 0.1 mg/ml. The rotation along the minor axis as measured with the same method is DR = // 1.5 × 106 sec-1 at 0.1 mg/ml. The rotation along the major axis as measured on fibrinogen labeled with dansylchloride is DR// = 1.5 x106 sec–1. S is also strongly dependent on concentration, being 7.9 S at 0.1 mg/ml, 8.1 S at 1 mg/ml and 6.6 S at 10 mg/ml.These results fit with an elongated molecule having an axial ratio of 7. They are compatible with a MW of 340’000 only for concentrations above 2 mg/ml, while at lower concentrations (0.1 mg/ml) they agree with a MW of approximately half the accepted value.

Monitoring complex formation in the blood-coagulation cascade using aptamer-coated SAW sensors

2005 ◽  
Vol 20 (10) ◽  
pp. 2044-2052 ◽  
Author(s):  
T.M.A. Gronewold ◽  
S. Glass ◽  
E. Quandt ◽  
M. Famulok
Keyword(s):  
Complex Formation ◽  
Blood Coagulation ◽  
Coagulation Cascade
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