Volume hydrated molecular

M(Nw 200-65000) and the same is true for the hydrated molecular volume. The values found for hydrated V exceed those given for the anhydrous protein models given in Table 1 by far. The amount of water bound to different proteins is relatively constant (5i 0.2-0.4gg ). The... 

Answer In solution, the negative charges on chondroitin sulfate repel each other and force the molecule into an extended conformation. The polar molecule also attracts many water molecules (water of hydration), further increasing the molecular volume. In the dehydrated solid, each negative charge is counterbalanced by a counterion, such as Na+, and the molecule collapses into its condensed form. 

Lithium nitrite, LiN02.—The monohydrate, LiN02,H20, is obtained by the interaction of lithium chloride and silver nitrite,7 and also by that of lithium sulphate and barium nitrite.8 It forms colourless, deliquescent needles, very soluble in water. At 0° C. its density is 1 615,9 and between 21° C. and 31° C. 1 671. Its molecular volume is 63-44.10 Under the influence of sunlight it decomposes, with formation of the red nitride. Oswald11 also prepared a colourless, deliquescent semihydrate, and proved that the colourless anhydrous salt becomes hydrated through the action of the moisture of the atmosphere. 

The radius of a hydrated perchlorate anion is 2.24 A [100], and thus the two perchlorate counter anions of the nickel(II) redox center can reside conveniently in the SAM itself Note that the coordination of axial ligands produces only small changes in the molecular volume and dimensions hence the Ni(IIl/II) redox reaction, where the Ni (III) ion is of octahedral geometry with axially coordinated supporting electrolyte anions/solvent molecules, would not affect the compactness and order of the SAM. 

While resistant to high temperature, catalysts based on magnesia are sensitive to steaming at low temperatures because of the risk of hydration (refer to Reaction R45 in Table 4.1) The reaction may result in breakdown of the catalyst because it involves an expansion of the molecular volume. The equilibrium constant for the reaction is plotted in Figure 4.1 [381], It is seen that at the pressures typical of tubular reformers, hydration cannot take place at temperatures above approximately 350 C. Kinetic studies of the hydration reaction have shown that magnesia reacts via liquid phase reaction in which water condenses in the pores. Therefore, the rate depends on the relative humidity of the atmosphere, and in practice hydration is a problem only when the magnesia-based catalyst is exposed to liquid water or is operated close to the condensation temperature [381]. Hydration is eliminated for carriers where magnesia has reacted with alumina to form... 

Abstract The present knowledge of protein science includes information on amino acid sequence and 3D structure in terms of precise models on the atomic level. Recourse to the respective databanks and advanced computer programs allows a series of molecular features to be calculated. Application of analytical surface calculation programs (SIMS, MSRoU) based on atomic coordinates or the coordinates of gravity centers of amino acids allows precise molecular dot surfaces to be calculated, in addition to numerical data for anhydrous molecular surface and anhydrous molecular volume. Usage of in-house hydration programs (HY-DCRYST, HYDMODEL) permits the putative localization of individual water molecules on the protein envelope to be addressed explicitly. To estimate the overall values of protein volume and hydration, simple approximations based on the amino acid composition and characteristic numbers for the constituents can be used. Derivation of secondary... 

Keywords Individual water molecules Molecular volume Overall hydration Proteins Surface topography Visualization and Modeling... 

Modem analytical procedures and programs for the visualization and analysis of protein molecules and models (see below) are based on crystallographic data sets as those in the PDB. These programs allow, among other things, the calculation of molecular volumes, V, and further volume and surface characteristics as well. The molecular volumes thus obtained are either anhydrous volumes, neglecting all hydration contributions, or consider the influence of the water molecules found. Even if the few waters found in crystallographic work (cf. [11]) are taken into account. 

Gerstein and Chothia [137] studied 22 proteins, the average number of surface atoms of per molecule of which was 420, and found them to be 47% hydrated, that is, in contact with water molecules. The peripheral hydrating water molecules had a molecular volume of 0.0245 nm compared with the molecular volume of bulk water, V"/Nj = 0.0300 nm at room temperature, that is, they were compressed by 22% with respect to it. 

The slope of Ais plot yields directly Ae ratio of volume fraction of hydrated micelles to Ae polymo concentration. The slope is (8-2/t)< )/C. Smce according to values of Ae molecular volumes of D2O, EO and PO groups listed in Table 1, densities of boA the polymo and Ae solvent are efiectively 1.00 to wiAm 1%. The slope can now be ex essed as Ae volume ratio of Ae bound solvent molecules to Ae polymer in a micelle, i.e.. 

Figure 5 Difference isodensity surface of 1.0 x 10 e A for the hydrated leu -zervamicin molecule. The difference isodensity surface was obtained from Pp — Pr- Small fuzzy regions represent the remaining difference. They involve a small molecular volume and are evidently small in magnitude...

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