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  • Polymer and Materials Science  (4)
  • Life and Medical Sciences  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Complexes of silver ion with natural and synthetic polynucleotides (1966)
    New York : Wiley-Blackwell
    Biopolymers 4 (1966), S. 51-76 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of silver-ion binding by nucleic acids and synthetic ribo and deoxyribopolynucleotides, has been carried out by means of potentiometric titration, thermal transition, and difference spectra. It is clearly demonstrated that a strong complex between Ag+ and nitrogen atoms of bases is made reversibly. Binding constants and site numbers are determined for each type of polynucleotide. Base reactivity varies strongly with chain length, and a cooperative phenomenon is found in each case. Two successive complexes with DNA are seen in all the three techniques, and they have the same characteristics as complexes with respectively poly-dGC and poly dAT. In the first complex, Ag+ is linked to four bases, provided two of them are a G-C pair. Calculated and experimental values of site numbers agree very well for DNA of different G-C content. Thermal stabilization occurs simultaneously, and the increase of melting temperature corresponds to calculated changes of stacking energy between base pairs. In the second complex a new ordered structure insensitive to temperature is formed, with simultaneous release of protons. The stoichiometry can be related to base sequence. Complexing with silver increases the resistance of TMV RNA to both temperature and ribonuclease; a tentative explanation is given in the latter case.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1966.360040107
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Donnan effect as measured by sedimentation equilibrium for the protein cytochrome cPresented, in part, for fulfillment of the requirements for Ph.D. to M.S. at U.C. - Berkeley in 1972. (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 943-956 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The protein turkey-heart cytochrome c is used as a model protein to study charge effects in sedimentation equilibrium experiments in three-component solutions. Data are given for the dependence of the apparent M (1-υρ) on ρ in solutions of KCl, RbCl, CsCl, and triethylamine hydrochloride. The results show the Donnan effect to have a significant influence on the apparent molecular weight, found by extrapolation of the data to a solution density of one. The apparent molecular weights are for protein at infinite dilution. A theoretical treatment is presented where the magnitude of this effect can be predicted accurately from the formal net charge of the protein as computed from the amino acid composition. The results are shown to be important in computing the preferential hydration of the protein in concentrated salt solutions. For such systems the Donnan effect should be subtracted from the total interaction coefficient for multicomponent system in order to obtain the preferential hydration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360170412
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  • 3
    Electronic Resource
    Electronic Resource
    Physical-Chemical studies on deoxyribonucleic acid. A discussionThe work reported here has been supported by a grant from the National Science Foundation and has been performed largely with V. N. Schumaker and E. Glen Richards. (1957)
    Philadelphia : Wiley-Blackwell
    Journal of Cellular and Comparative Physiology 49 (1957), S. 71-81 
    Details
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1030490408
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  • 4
    Electronic Resource
    Electronic Resource
    Ultracentrifuge studies with a synthetic boundary cell. I. General applications (1954)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 12 (1954), S. 379-390 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This report presents some general applications of a new type of ultracentrifuge cell, called a synthetic boundary cell, in which a sharp, stable boundary is obtained by layering one solution over another more dense solution while the ultracentrifuge is in operation. Since such a boundary between a solvent and a dilute solution of a low molecular weight solute can be formed in the center of the cell, the complications encountered at the meniscus in conventional ultracentrifugation by the high diffusion and low sedimentation rate of the solute are obviated. By this technique the sedimentation velocity method has been extended to substances with molecular weights as low as 350. Sedimentation constants of a number of low molecular weight materials such as fraction A of insulin (molecular weight 3000), vitamin B12 (molecular weight about 1500), β-dextrin (molecular weight 1134), and sucrose (molecular weight 342) have been determined. The cell has also been used to form a boundary between solutions of two different concentrations of the same macromolecule and differential sedimentation constants have been obtained. The relationship between these differential sedimentation constants and those obtained for either of the two solutions when studied alone is discussed. Application of the cell to the determination of hydrodynamic volumes of sedimenting components is described. Measurements are made of the backward flow of solvent by the use of an indicator boundary formed by layering a virus solution over another virus solution containing an additional component, such as sucrose or a protein, which acts as an indicator. In addition, the cell was used in a preliminary investigation of some fundamental problems in ultracentrifugation such as the sedimentation of slowly sedimenting materials in the presence of more rapidly sedimenting components, the analysis of equilibrium systems such as insulin and chymotrypsin, and the role of convection.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1954.120120130
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  • 5
    Electronic Resource
    Electronic Resource
    Studies on the validity of the Einstein viscosity law and Stokes' law of sedimentationThis work was supported by grants from the Corn Industries Research Foundation, Lederle Laboratories Division of the American Cyanamid Company, and the Rockefeller Foundation. (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 16 (1955), S. 19-30 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ultracentrifugal studies on polystyrene latex particles (PSL) in solutions of different densities prepared either from mixtures of H2O and D2O or from various concentrations of sucrose in water yielded a value, by interpolation, of 1.0520 for the density of solution in which the particles neither sediment nor float. Considerations of these results plus the nature of the particles lead to the conclusion that the partial specific volume of the polystyrene latex particles is (1/1.0520) cc./g., a value in agreement with the bulk specific volume of solid polystyrene. Evidence is presented for PSL to support the view that the effective hydrodynamic volume is equal to the partial specific volume, so that volume fractions can be determined from the partial specific volume and the dry weight concentration. Measurements of the viscosity of suspensions of polystyrene latex particles over a broad concentration range showed that the intrinsic viscosity was 2.5, in confirmation of the theory of Einstein. At concentrations above 2% by volume a square term in concentration, with coefficient about 10, and also a cubic term are needed to satisfy the data. From the partial specific volume of the latex particles and the value of the sedimentation coefficient extrapolated to infinite dilution, a value of 2640 ± 12 A. was calculated for the diameter of the particles from Stokes' law. This value is in excellent agreement with values obtained by electron microscopy, light scattering, and low angle x-ray scattering. This agreement amounts to a satisfactory test of Stokes' law for particles not much larger than some of the viruses. Studies of the dependence of sedimentation coefficient on concentration indicate that existing theories are not completely satisfactory and that the influence of backward flow of liquid during the sedimentation of the solute particles is appreciable.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120168102
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