A study of partially liganded sickle hemoglobin polymerization kinetics

Highly ordered bundles of deoxyhemoglobin S (HbS) fibers, termed fascicles, are intermediates in the high pH crystallization pathway of HbS. These fibers consist of 7 Wishner-Love double strands in a helical configuration. Since each double strand has a polarity, the odd number of double strands in the fiber imparts a net polarity to the structure. HbS crystals have a unit cell containing two double strands, one of each polarity, resulting in a net polarity of zero. Therefore a rearrangement of the double strands must occur to form a non-polar crystal from the polar fibers. To determine the role of fascicles as an intermediate in the crystallization pathway it is important to understand the relative orientation of fibers within fascicles. Furthermore, an understanding of fascicle structure may have implications for the design of potential sickling inhibitors, since it is bundles of fibers which cause the red cell distortion responsible for the vaso-occlusive complications characteristic of sickle cell anemia.

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Faculty Opinions recommendation of Sickle hemoglobin confers tolerance to Plasmodium infection.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.10292956.11092054 ◽

2011 ◽

Author(s):

Paul Roepe

Keyword(s):

Plasmodium Infection ◽

Sickle Hemoglobin

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The mechanism of the anionic coordination polymerization of isoprene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19802391 ◽

1980 ◽

Vol 45 (9) ◽

pp. 2391-2399 ◽

Cited By ~ 1

Author(s):

Miroslav Kašpar ◽

Jiří Trekoval

Keyword(s):

Chromatographic Method ◽

Initial Period ◽

Reaction Scheme ◽

Polymerization Kinetics ◽

Coordination Polymerization ◽

Initial Concentration ◽

The Cross ◽

Gas Chromatographic Method ◽

Kinetics Of

The polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene with butyllithium as the initiator was investigated by the gas chromatographic method. After completion of the initial period of the reaction, its order with respect to the initial concentration of initiator is negative at the concentrations of the latter between 0.01 and 0.25 mol/l, and positive at higher concentrations. A reaction scheme has been suggested with respect to the "cross" association of butyllithium and of the "living" oligoisoprene.

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The effect of electrondonors on the polymerization kinetics of isoprene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19803338 ◽

1980 ◽

Vol 45 (12) ◽

pp. 3338-3346

Author(s):

Miroslav Kašpar ◽

Jiří Trekoval

Keyword(s):

Induction Period ◽

Ethyl Ether ◽

Reaction Order ◽

Propagation Rate ◽

Reaction Scheme ◽

Polymerization Kinetics ◽

Polymerization Rate ◽

Constant Concentration ◽

Initial Concentration ◽

Kinetics Of

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.

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Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽

10.3390/polym13111686 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1686

Author(s):

Andrey Galukhin ◽

Roman Nosov ◽

Ilya Nikolaev ◽

Elena Melnikova ◽

Daut Islamov ◽

...

Keyword(s):

Kinetic Analysis ◽

Single Step ◽

Polymerization Kinetics ◽

Scanning Calorimetry ◽

Modulated Differential Scanning Calorimetry ◽

Diffusion Controlled ◽

Polymerization Product ◽

The One ◽

Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

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