Hydrodynamic properties of protein

Again, so long as one speaks qualitatively, it is well established that solute protein is hydrated in water solution (cf. D. Results from measurements of the hydrodynamic properties of protein solutions and the hydrodynamic properties of proteins molecules in solution, from the early work on viscosity, flow birefringence, and dielectric relaxation (cf. O to the more modem work on translational and rotational diffusion measured by inelastic... 

In a dilute protein solution, the nano length scale or the molecular structure of protein molecules determines the thermodynamic equilibrium between protein-protein and protein-water interactions. The consequent surface and hydrodynamic properties of proteins are resulted from the proportion of hydrophobic, hydrophilic, and charged amino acid residues. For example, caseins could adopt a random coil structure due to their flexible structure as a result of phosphorylated serine residues caseins indeed lack the ordered structures of a-helix, 3-sheet, and 3-turn found in globular proteins. This gives rise to better multifunctionality of caseins over globular proteins. 

The theory for rotational diffusion of non-spherical particles is complex. In theory the anisotropy decay of such a molecule can be composed of a sum of up to five exponentials [134]. The ellipsoids of revolution represent a smooth and symmetrical figure, which is often used for the description of the hydrodynamic properties of proteins. They are three-dimensional bodies generated by rotating an ellipse about one of its characteristic axes. In this case the anisotropy decay displays... 

The hydrodynamic properties of protein solutions have consistently suggested that the apparent dimensions of the protein are larger than expected. They can be explained by assuming that there is a hydration shell of water that moves with the protein. The exact value of the size of the shell varies but calculations which take accoxmt of protein structure and electrostatie properties suggest values of around 0.4 g of water per g of protein are involved. These figures are remarkably similar to the amoimts of non-freezing water observed and therefore are suggestive of a real effect due to some kind of water with different properties. 

Centrifugation can be used either as a preparative technique for separating and purifying macromolecules and cellular components or as an analytical technique to characterize the hydrodynamic properties of macromolecules such as proteins and nucleic acids. 

Works where study the hydrodynamic properties of a biopolymers in aqueous solution at different temperatures are made by Guner (1999), and Guner Kibarer (2001) for dextran Ghen Tsaih (1998) and Kasaii (2008) for chitosan, Bohidar for gelatin (1998), and Monkos for serum proteins (1996,1997,1999, 2000, 2004 and 2005). 

The hydrodynamic properties of Ustilago cytochrome c were investigated by Thelander (86). He found the partial specific volume to be 0.721 ml/g and the molecular weight, by sedimentation equilibrium, to be 15,500. The latter value, although higher than that given by summation of the constituent amino acid residues (i.e., 11,877, see Table 3), indicates that the protein is monomeric. 

PEG (20 kDa) [43]. This demonstrates the strong hydrodynamic properties of PEGylated molecules. The increase in hydrodynamic radius significantly decreases renal clearance. Although the threshold of the molecular weight cut-off of renal filtration of protein is about 65 kDa, the 30-kDa PEG demonstrates minimal renal permeability [44]. 

From this emulsion particle model, it was possible to predict the lipoprotein composition, buoyant density, and hydrodynamic properties of the LDL as a function of lipoprotein size, given the partial specific volumes of the lipid, protein, and carbohydrate components. A cross-sectional slice through the model is shown in Fig. 3 as two concentric circles, representing the hydrophobic core surrounded by a monolayer of phospholipid, cholesterol, and protein. The model parameters are given in the footnote to Table II and include the thickness of the shell, the... 

Hydrodynamics. Estimates of protein hydration water based on frictional properties are generally greater than estimates from thermodyn unlcs (2). Squire fuid Himmel (27) found that the hydration of 21 proteins has a me ui value 0.53 g of water/g of protein. 

The introduction of succinyl residues producing short-range repulsive forces in place of possible short-range attractive forces in the native molecule resulted in a change of hydrodynamic properties of bovine serum albumin (BSA), bovine y-globulin, and /3-lactoglobulin [3], The succinylated derivatives showed markedly increased intrinsic viscosity and Stokes radius and a decrease of sedimentation coefficient [36,37], These results are compatible only with a considerable increase in the effective volume occupied by the succinylated protein molecule compared to its unreacted counterpart. 

Garcia de la Torre, J., Huertas, M.L., Carrasco, B. Calculation of hydrodynamic properties of globular proteins from their atomic-level structure. Biophys. J. 2000, 78, 719-30. 

In sedimentation velocity experiments, the centrifnge is rnn at high speeds (up to -80,000 rpm), and the rate of sedimentation of the bonndary between the solvent and the sedimenting protein is measured to yield the sedimentation coefficient of the molecule (or molecules). This value is related to the size and shape of the molecule and is measnred in Svedberg units (denoted by S, and formally it is equal to 10 s). E.g., the 30S subunit of the ribosome has a sedimentation coefficient of 30 S. The Svedberg of Sweden invented the analytical ultacentrifnge, and he received the 1926 Nobel Prize in Chemistry for his work characterizing the hydrodynamic and mass properties of proteins. 

This volume consists of four parts. The first part is devoted to theoretical studies and computer simulations. These studies deal with the structure and dynamics of polymers adsorbed at interfaces, equations of state for particles in polymer solutions, interactions in diblock copolymer micelles, and partitioning of biocolloidal particles in biphasic polymer solutions. The second part discusses experimental studies of polymers adsorbed at colloidal surfaces. These studies serve to elucidate the kinetics of polymer adsorption, the hydrodynamic properties of polymer-covered particles, and the configuration of the adsorbed chains. The third part deals with flocculation and stabilization of particles in adsorbing and nonadsorbing polymer solutions. Particular focus is placed on polyelectrolytes in adsorbing solutions, and on nonionic polymers in nonadsorbing solutions. In the final section of the book, the interactions of macromolecules with complex colloidal particles such as micelles, liposomes, and proteins are considered. 

Here, the value 0.73 was used for the partial specific volume, v, and 0.53 gram of water per gram of protein as the hydration value, w. These are mean values calculated from an earlier study of the hydrodynamic properties of 21 globular proteins of known structure (ref. 74). Calibration constants in terms of molecular radii (r and r. ), given in Table 1, provide an estimate of the limiting values of these parameters for separation by the primary SEC process on the TSK-SW columns used. 

An Intrinsic limitation In SEC of proteins Is their natural variation In conformation and effective hydrodynamic volume. This variation affects the chromatographic properties of proteins and Is frequently responsible for deviations in the theoretical linear relationship between molecular weight and retention coefficients which can be obtained with synthetic polymers. 

---