Solution-based macromolecules

It can be concluded that MD is a very powerful tool to refine structures of proteins and polypeptides in solution, based on 2D NMR data. This combination of techniques emerges as an important means to determine the 3 D structure of macromolecules up to a molecular weight of 20,000 in solution or in micelles or membrane fragments. 

In order to obtain a higher effectiveness of drag reduction, it was therefore more convenient to produce the actual experimental solution from the more diluted stock solution. This is already an indication that the state of solution of macromolecules plays an important role in the interpretation of the results. However, a molecular weight of 10.1 106 g/mol and a concentration of 1000 ppm is just below the critical concentration c (this c is based on viscometric measurements) (Kulicke 1982). Above this critical concentration, mechanical entanglements ensure between the macromolecules. Beneath this limit, interactions between the molecules come into... 

Pretzl M, Schweikart A, Hanske C, Chiche A, Zettl U, Horn A, Boker A, Fery A (2008) A lithography-free pathway for chemical microstructuring of macromolecules from aqueous solution based on wrinkling. Langmuir 24 12748-12753... 

Both polymeric and silica-based columns are in common use.The polymeric columns are heavily used in the analysis of synthetic polymers and plastics where organic solvents are required. Silica-based columns with hydrophilic bonded phases are used to separate aqueous solutions of macromolecules. Finally, polymeric size-separation columns with hydrophilic phases are available for separation of polysaccharides, peptides, and very small proteins. 

Dynamic light scattering (DLS), also called photon correlation spectroscopy (PCS) or laser light scattering (LLS) is a technique based on the principle that moving objects cause a frequency shift due to the Doppler effect. If a solution of macromolecules with random Brownian motion is illuminated with monochromatic laser light, the scattered light should contain a distribution of frequencies about the incident frequency the spectral line is virtually broadened. The width of the distribution is related to the MMD. 

Equilibrium Dialysis Method. The equilibrium dialysis method is based on the diffusion of the volatile compound through a semi-permeable membrane placed between two compartments containing the model wine and macromolecules (11). In the experiment, ImL solution of macromolecule in the model wine was placed on one side of the membrane (compartment 1) and 1 mL of the model wine containing a known amount of the volatile compound on the other side (compartment 2). The system was shaken at 30 °C for 12 h to reach equilibrium of the free ligand (volatile compound) between the two compartments of the cell. At equilibrium, the concentration of the volatile compound was determined by gas chromatography. The difference in concentration of the volatile compound between the two compartments represents the amount of the volatile compound bound to the macromolecule. 

It is not implausible to propose that at a relatively early time in evolution, cells were able to devise ways of escaping the chaos of solution chemistry. One method would be the attachment of their enzymes to a framework that is under the cell s control. Whereas prokaryotic cells are small enough to allow solution-based metabolism to occur, the dimensions of eukaryotic cells are unfavorable for many random processes. Based on what is now known about the intracellular environment, one may suggest that the MTL and cytoskeletal networks might be linked in the aqueous regions to key enzymes at their surfaces and that the regions between strands of the MTL are relatively dilute with respect to macromolecules. 

Recent experimental advances have made quantitation of weak membrane adhesion possible in concentrated solutions of macromolecules. We report direct measurements of the free energy potential for adhesion of phospholipid Dilayers in solutions of two plasma proteins (fibrinogen and albumin) over a wide range of volume fraction (Q-0.1). Tne results are consistent with a thermodynamic model for adhesion based on depletion of macromolecules from the contact zone. 

Two diverse views of non-specific adhesion processes form the bases for contemporary theories introduced to rationalize observations of colloidal stability and flocculation in solutions of macromolecules (see 16-18 for general reviews). The first view is based on adsorption and cross-bridging of the macromolecules between surfaces. Theories derived from this concept indicate a strong initial dependence on concentration of macromolecules there is a rapid rise in surface adsorption for infinitesimal volume fractions (32) followed by a plateau with gradual attenuation of surface-surface attraction because of excluded volume effects in the gap at larger volume fractions (19-20). The interaction of the macroinolecule with the surface is assumed to be a snort range attraction proportional to area of direct contact. The second - completely disparate - view of non-specific adhesion is based on the concept that there is an exclusion or depletion of macromolecules in the vicinity of the surface, i.e. no adsorption to the surfaces. Here, theory shows that attraction is caused by interaction of tne (depleted) concentration profiles associated with each surface which leads to a depreciated macrornolecular concentration at the center of the gap. The concentration... 

HAL Kalacheva, S., Rangelov, S., and Tsvetanov, C., Poly(glycidol)-based analogues to pluronic block copolymers. Synthesis and aqueous solution properties, Macromolecules, 39, 6845, 2006. 

We shall thus, in a first division, consider the macromolecule itself, its mass, constitution, configuration and physical properties. In this main division nevertheless solutions of macromolecules and some of their properties already enter into the discussion based upon thermodynamical and rheological considerations on a model of the randomly kinked macromolecule. 

An experimental study of thermodynamic quantities in solutions of macromolecules has almost always been based on either the vapour pressure or the osmotic pressure Let us first consider the vapour pressure method. If the solution is in equilibrium with the vapour of the pure solvent, the molar free energy of the solvent must be the same in the two phases. Denoting the quantities pertaining to the solvent by a subscript o and the vapour phase by a stroke,... 

Size of macromolecules in solution, based on their selective permeation through the porous particles of the column packing and resultant exclusion processes, which form the grormd of size exclusion chromatography and most field flow fractionation methods. This section mainly deals with the SEC, (see section 11.7, Size Exclusion Chromatography). 

MO1 Mori, H., Kato, I., Saito, S., and Endo, T., Proline-based block copolymers displaying upper and lower critical solution temperatures, Macromolecules, 43, 1289, 2010. 

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