Molecular weight and charge

Renard, D. Lavenant-Gourgeon, L. Ralet, M. Sanchez, C. (2006). Acacia Senegal Gum Continuum of Molecular Species Differing by Their Protein to Sugar Ratio, Molecular Weight, and Charges. Biomacromolecules, Vol.7, No.9, (Augudt 2006), pp. 2637-2649, ISSN 1525-7797. 

Rodbard and Chrambach [77,329] developed a computer program that allows the determination of molecular parameters, i.e., free mobility, molecular radii, molecular weight, and charge or valence, from measured electrophoretic mobilities in gels with different monomer concentrations. For a set of mobility versus gel concentration data they used the Ferguson [18,115,154] equation to obtain the retardation constant from the negative slope and the free mobility from the extrapolated intercept. From the retardation constant they determined the molecular radius using... 

Dependence of the viscosity on molecular weight and charge density of the polymer... 

The effect which polyelectrolyte adsorption has upon the surface charge (zeta potential) of fibres and fines is also important—particularly for retention—and both molecular weight and charge density of the adsorbed polyelectrolyte are known to affect the particle surface charge, although not always in an intuitively predictable way. 

Fieldes, M. A., and Dixon, B., 1988, Malate dehydrogenase isozymes in flax genotroph leaves differences in apparent molecular weight and charge between and within L and S, Biochem. Genet. 26 249-260. 

Maitani, Y., Y. Machida, and T. Nagai. 1989. Influence of molecular weight and charge on nasal absorption of dextran and DEAE-dextran in rabbits. Int J Pharm 49 23. 

Alternatively, one can separate the proteins before breaking them into peptides and then subject them to protein breakdown to obtain the peptide. This approach involves mainly the use of gel-based procedures such as one-dimensional or two-dimensional electrophoresis (2-DE) to resolve protein mixture into protein spots based on molecular weight and charge (isoelectric point or pi). Following separation, protein spots are cut out from the gel protein is harvested from gel matrix, digested by peptides, and subjected for further mass spectrometric analysis. 

In [93-95] a combination of turbidimetry and static and dynamic light scattering was applied to study the structure of complexes between PDADMAC samples of different molecular weights and charged mixed micelles. A review on such studies of polyelectrolyte-protein complexes is given in [96]. 

The effects of molecular weights and charge characteristics of flocculants on the flocculation behavior of particles of different sizes are summarized in Table 5.31. 

Table I. Cationic celluloslc polymers investigated for molecular weight and charge density effects.

The extracts (SCMKB, 7-keratose) obtained by both procedures demonstrate marked heterogeneity [222,223]. SCMKB from Merino wool has been shown to contain more than 60 polypeptides [222]. These high-sulfur polypeptides have been found to display heterogeneity with respect to both molecular weight and charge. 

The polymers undergo structural changes from helix to random coil as the solution temperature increases, and eventually adopt P-sheet conformations at sufficiently elevated temperatures and concentrations. The conformational changes are strongly influenced by the molecular weight and charge density of the protein polymer. 

Ng, L.-T., Ng, K.-S. (2008). Photo-cured pH-responsive polyampholyte-coated membranes for controlled release of drugs with different molecular weights and charges. Radiation Physics and Chemistry, 77, 192-199. 

Table 3.8 Fixing agents categories, molecular weight and charge density (source BASF).

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