Calculation of Partial Specific Volumes and Other Volumetric Properties of Small Molecules and Polymers

Abstract

Volumetric properties of macromolecules and low-molecular compounds are necessary auxiliary means for the determination of molar masses from solution-scattering and hydrodynamic techniques. In many cases experimental determinations of partial volumes can or have to be replaced by calculative procedures. A universal approach for the calculation of both low-molecular organic compounds and polymers of different chemical composition and structure in aqueous solution is described. It is based on volume increments for the constituent atoms, ions and/or groups and allows corrections for covolume, ring formation, micellization, ionization etc . Application of this approach is of particular interest in connection with: (i) nonionic and ionic organic solutes; (ii) inorganic electrolytes; (iii) monomeric and micellar detergents and lipids; (iv) carbohydrates and polysaccharides; (v) nucleobases, nucleosides, nucleotides, polynucleotides, nucleic acids; (vi) amino acids, amino-acid residues, peptides, polyaminoacids, nonconjugated and conjugated proteins; (vii) synthetic polymers. The results of the volume predictions show a high degree of reliability, if compared to experimental data. Special approaches dealing with simple and conjugated proteins and protein-ligand complexes in two- and multicomponent solutions allow the prediction of both isomolal and isopotential volumes under a variety of native and denaturing conditions, including the presence of high amounts of additives.