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    Exploring the potential of dietary fibres:can protein-polysaccharide interactions be the key to providing a new solution to dietary disorders?
    (Elsevier Science Bv, 2010) Kök, Mehmet Şamil; Harding, S. E.; Adams, Gary; Tatham, A. S.; Morris, G.
    This research is concerned with investigating the use of dietary fibres (DFs) in order to help with the provision of possible “safer foods”. With millions of people suffering from dietary disorders globally it is a challenge as well as a responsibility for bio-molecular scientists to come up with novel solutions.
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    Extended Fujita approach to the molecular weight distribution of polysaccharides and other polymeric systems
    (Academic Press Inc Elsevier Science, 2011) Harding, Stephen E.; Schuck, Peter; Abdelhameed, Ali Saber; Adams, Gary; Kök, M. Şamil
    In 1962 H. Fujita (H. Fujita, Mathematical Theory of Sedimentation Analysis, Academic Press, New York, 1962) examined the possibility of transforming a quasi-continuous distribution g(s) of sedimentation coefficient s into a distribution f(M) of molecular weight M for linear polymers using the relation f(M) = g(s) . (ds/dM) and showed that this could be done if information about the relation between s and M is available from other sources. Fujita provided the transformation based on the scaling relation s = kappa M-s(0.5), where kappa(s) is taken as a constant for that particular polymer and the exponent 0.5 essentially corresponds to a randomly coiled polymer under ideal conditions. This method has been successfully applied to mucus glycoproteins (SE. Harding, Adv. Carbohyd. Chem. Biochem. 47 (1989) 345-381). We now describe an extension of the method to general conformation types via the scaling relation s = kappa M-b, where b = 0.4-0.5 for a coil, similar to 0.15-0.2 for a rod and similar to 0.67 for a sphere. We give examples of distributions f(M) versus M obtained for polysaccharides from SEDFIT derived least squares g(s) versus s profiles (P. Schuck, Biophys. J. 78 (2000) 1606-1619) and the analytical derivative for ds/dM performed with Microcal ORIGIN. We also describe a more direct route from a direct numerical solution of the integral equation describing the molecular weight distribution problem. Both routes give identical distributions although the latter offers the advantage of being incorporated completely within SEDFIT. The method currently assumes that solutions behave ideally: sedimentation velocity has the major advantage over sedimentation equilibrium in that concentrations less than 0.2 mg/ml can be employed, and for many systems non-ideality effects can be reasonably ignored. For large, non-globular polymer systems, diffusive contributions are also likely to be small. (C) 2011 Elsevier Inc. All rights reserved.
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    Matrix-free hydrodynamic study on the size distribution and conformation of three technical lignins from wood and non-wood
    (Walter De Gruyter Gmbh, 2016) Alzahrani, Qushmua; Adams, Gary; Gillis, Richard B.; Besong, Tabot; Kök, Mehmet Şamil
    Molecular weight (MW) and related conformational data of three commercially available technical lignins (Alcell L, kraft L, and soda L) have been studied by means of analytical ultracentrifugation, taking advantage of some recent developments in both sedimentation velocity and sedimentation equilibrium determinations. The lignins were dissolved in dimethyl sulphoxide (with ca. 90% solubility), and solutions were studied with regards to their oligomeric state, heterogeneity profiles (distribution of sedimentation coefficients), and molecular weight distributions (MWD). Alcell L and soda L have similar properties showing one major low MW component and two minor high MW components, whereas kraft L appears to be larger and more uniform, i.e., it shows a more mono-disperse MWD. Weight average molecular weight (M-w) data from sedimentation equilibrium obtained by the new SEDFIT-MSTAR procedure in conjunction with MULTISIG analysis were found to be similar to 18 kDa (Alcell L), 25 kDa (kraft L), and 15 kDa (soda L). Further analysis of the data by means of the routines MULTISIG and M_INVEQ confirmed the presence of additional components in Alcell L and soda L, and the larger size and high degree of mono-dispersity of kraft L. The intrinsic viscosity data of the three lignins were found to be very similar in the range of 22-24 ml g(-1), and all data were consistent with an elongated plate shape molecular structure with an equivalent discoid aspect ratio similar to 30.