Biopolymers globular proteins

JD Eloneycutt, D Thirumalai. The nature of folded states of globular proteins. Biopolymers 32 695-709, 1992. 

Adsorption of Biopolymers, with Special Emphasis on Globular Proteins... 

Privalov, P.L., N.N. Khechinashvili, and B.P. Atanasov. 1971. Thermodynamic analysis of thermal transitions in globular proteins. I. Calorimetric study of chy-motrypsinogen, ribonuclease and myoglobin. Biopolymers 10 1865-1890. 

The parameters R and Rj in equation (5.32) are the radii of the equivalent hard spheres representing biopolymers i and y, respectively (where i = j for interactions between the same macroions). The equivalent hard sphere corresponds to the space occupied in the aqueous medium by a single biopolymer molecule (or particle) which is completely inaccessible to other biopolymers. In practice, the hard sphere model is a highly satisfactory description for many globular proteins. 

Weinbreck, F., de Kruif, C.G. (2003). Complex coacervation of globular proteins and gum arabic. In Dickinson, E., van Vliet, T. (Eds). Food Colloids, Biopolymers and Materials, Cambridge, UK Royal Society of Chemistry, pp. 337-344. 

Both the denaturation process in proteins and the melting transition (also referred to as the helix-to-coil transition) in nucleic acids have been modeled as a two-state transition, often referred to as the all-or-none or cooperative model. That is, the protein exists either in a completely folded or completely unfolded state, and the nucleic acid exists either as a fully ordered duplex or a fully dissociated monoplex. In both systems, the conformational flexibility, particularly in the high-temperature form, is great, so that numerous microstates associated with different conformers of the biopolymer are expected. However, the distinctions between the microstates are ignored and only the macrostates described earlier are considered. For small globular proteins and for some nucleic acid dissociation processes,11 the equilibrium between the two states can be represented as... 

For such biopolymers as globular proteins with many dipolar groups contributing to a resultant p, the theory provides a simple understanding of the observed behavior the large values of... 

Go N, Abe H (1981) Noninteracting local-structure model of folding and unfolding transition in globular proteins. I. formulation, Biopolymers 20 991-1011... 

Kharakoz, D.P., Sarvazyan, A.P. 1993. Hydrational and intrinsic compressibilities of globular-proteins. Biopolymers 33, 11-26. 

M. Vasquez, M. R. Pincus, and H. A. Scheraga, Biopolymers, 26, 351 (1987). Helix-Coil Transition Theory Including Long-Range Electrostatic Interactions Application to Globular Proteins. 

Zhou, Y., and Hall, C. K. (1996), Solute excluded-volume effects on the stability of globular proteins A statistical thermodynamic theory, Biopolymers, 38,273-284. 

The phase separation threshold is lower for systems containing a branched polysaccharide than for systems containing a linear polysaccharide of the same molecular weight. It is higher for globular proteins compared to proteins of unfolded structure. An increase in excluded volume means a decrease in the free volume of the solution accessible for biopolymers. Thus, the excluded volume of biopolymer molecules implies that water in real foods can be nonsolvent water relative to macromolecules. 

The same mechanism must in prindple apply to globular proteins. However, because of the small dimensions of these biopolymers the dielectric increments are of comparatively small magnitude. Furthermore, their dispersion falls in the same frequency range as that of the rotational polarization mechanism of permanent dipole moments. Since the latter is apparently predominant, it would be difficult to distinguish the coimterion effect. 

J.D. Honeycutt and D. Thirumalai, The Nature of Folded States of Globular Proteins, Biopolymers, 32 (1992) 695 J.D. Honeycutt and D. Thirumalai, Metastability of the Folded States of Globular Proteins, Proc. Natl. Acad. Sci. USA, 87 (1990) 3526. 

Yu, S.-Y., Yao, P., Jiang, M., and Zhang, G.-Z. (2006). Nanogels prepared by self-assembly of oppositely charged globular proteins. Biopolymers 83,148-158. 

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