| 1. |
- Skepö, Marie, et al.
(författare)
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Adsorption of the Flexible Salivary Proteins Statherin and PRP-1 to Negatively Charged Surfaces. A Monte Carlo Simulation and Ellipsometric Study
- 2007
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Ingår i: Zeitschrift fur physikalische Chemie (Munchen. 1991). - : Oldenbourg Wissenschaftsverlag, München. - 0942-9352 .- 2196-7156. ; 221:1, s. 21-46
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Tidskriftsartikel (refereegranskat)abstract
- The structural properties of the salivary proteins, acidic proline rich PRP-1 and statherin, adsorbed onto negatively charged surfaces have been studied by Monte Carlo simulations and ellipsometry. It is shown that both proteins adsorb to negatively charged surfaces, although their net charges are negative. Experimentally, an initial fast mass-controlled film build-up was detected for both proteins, and plateaus were reached within 10 minutes. The isotherm shape and the adsorbed amounts were similar for PRP-1 to hydrophilic and hydrophobic surfaces, while statherin adsorbs to a greater extent to the hydrophobic surface. These results could be explained from the simulation results by considering the proteins as diblock polyampholytes. It has also been shown that the adsorption of PRP-1 to a negatively charged surface may be purely electrostatically driven, while pure electrostatic interaction is not sufficient to drive adsorption of statherin, i.e., an extra short-ranged attractive interaction is necessary to account for the experimental observations.
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| 2. |
- Svendsen, Ida, et al.
(författare)
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Lactoperoxidase and Histatin 5 : their Adsorption Behaviour on Silica and Hydrophobized Silica Surfaces, and Implications on their Role in the Initial Salivary Film Formation
- 2007
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Ingår i: Zeitschrift fur physikalische Chemie (Munchen. 1991). - : Oldenbourg Wissenschaftsverlag, München. - 0942-9352 .- 2196-7156. ; 221, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- The acquired pellicle is the thin salivary film that covers all oral surfaces, formed by selective adsorption of primarily salivary proteins. Several cationic proteins, such as lactoferrin, lactoperoxidase, lysozyme and histatin 5 have been identified in the pellicle. This study focused on the adsorption of lactoperoxidase and histatin 5, to investigate their possible importance in the initial salivary film formation. The adsorption was investigated by means of in situ ellipsometry, to both pure (hydrophilic) and methylated (hydrophobized) silica substrates, at concentrations relevant in saliva. The adsorption was investigated in terms of surface area per molecule and influence of surface wettability. Mass transport controlled adsorption in relation to the initial adsorption from human whole saliva and glandular saliva was also investigated. Results showed that lactoperoxidase adsorbed in larger amounts on pure silica compared to methylated surfaces. Histatin 5 adsorbed to the same extent to the two types of surfaces, but to a lesser extent compared to lactoperoxidase. The mass transport calculated adsorption rates of lactoperoxidase and histatin 5 showed that histatin 5 might potentially have a significant role in the initial adsorption from saliva, whereas lactoperoxidase may also adsorb but is not a dominating component.
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| 3. |
- Olovsson, Ivar
(författare)
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Comparison of the proton transfer path in hydrogen bonds from theoretical potential energy surfaces and the concept of conservation of bond order
- 2006
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Ingår i: Zeitschrift fur physikalische Chemie (Munchen. 1991). - : Walter de Gruyter GmbH. - 0942-9352. ; 220:7, s. 797-810
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Tidskriftsartikel (refereegranskat)abstract
- The 'quantum-mechanically derived reaction coordinates' (QMRC) for the proton transfer in hydrogen bonds involving fluorine, oxygen and chlorine have been derived from earlier ab initio calculations of potential energy surfaces. A comparison is made between QMRC and the corresponding reaction coordinates (BORC) derived by applying the Pauling bond order concept together with the principle of conservation of bond order. Theoretical calculation have shown that sum of the bond orders remains close to constant along the reaction coordinate in agreement with the Pauling postulate. The BORC correlation curves agree very well with theoretical results. The results indicate that the BORC curve gives a good representation of the reaction coordinates (ptoton transfer path) for any X-H---Y aggregate.
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| 4. |
- Olovsson, Ivar
(författare)
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The Role of the Lone Pairs in Hydrogen Bonding
- 2006
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Ingår i: Zeitschrift fur physikalische Chemie (Munchen. 1991). - : Walter de Gruyter GmbH. - 0942-9352. ; 220:7, s. 963-978
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Tidskriftsartikel (refereegranskat)abstract
- The paper discusses some aspects of the electron lone-pairs in H-bonded structures: their role in determining the short-range structure and the effect of the environment on the electron density. In the water molecule the entire non blonded region apperars to be equally accessible for hydrogen bonding and the details of the hydrogen-bond arrangement are mainly determined by simple geometrical and topological requirements. Many examples may be taken to illustrate that it is important to take the whole electron and nuclear distribution into account when discussing the relative arrangement of interacting molecules. The resulting structure of one particular compound is determined by the net balance of many intermolecular interactions and not only by the hydrogen bonding, even if the resulting structure is consistent with hydrogen-bond directionality. From structural data it can be concluded that immediate accptor of a hydrogen bond is some negative charge accumulation, such as in a lone-pair region, but not specifically any individual lone pairs in the traditional, atomic sense.
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