Structure and Properties of Water at Biological Interfaces

Drost-Hansen, W.

doi:10.1016/b978-0-12-136102-0.50007-7

Cited by 58 publications

(32 citation statements)

References 258 publications

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“…Each of these parameters influences, to varying degrees, the physical status (viscosity, interface stability, hydrophobicity, etc.) of the membrane (3,4,9). Sterol glycosides and ,8-hydroxy sterols, also affecting membrane physical properties at low temperatures (4, 13), were not detected in any lamellar preparation (6).…”

Section: Discussionmentioning

confidence: 91%

“…Increased length of the n-alkyl chain causes increased membrane hydrophobicity (28) which implies greater over-all bilayer stability in an aqueous system (15,28). Lamellar stability also has been linked to interfacial H-bonding resulting from enhanced insulation of the hydrophobic region (3,9). Because ofthe increased ratio ofC18 to C16 fatty acids, the appearance of highly unsaturated C20 fatty acids, and the increased interfacial H-bonding capacity of glycolipids compared to phospholipids, it appears that greater hydrophobicity also may contribute to membrane integrity during hardening.…”

Section: Discussionmentioning

confidence: 99%

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Glycerolipid and Fatty Acid Changes in Eastern White Pine Chloroplast Lamellae during the Onset of Winter

DeYoe¹,

Brown²

1979

Plant Physiol.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Glycerolipid and Fatty Acid Changes in Eastern White Pine Chloroplast Lamellae during the Onset of Winter

DeYoe¹,

Brown²

1979

Plant Physiol.

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“…In principle, there is no doubt that physical properties (and especially the dielectric permeability) of water in proximity to the interface differ significantly from those of the bulk water [29-311. However, it is amazing that the structured water layer is supposed to be 300 -1000 molecules of water thick [30]. Moreover, a high chemical activity of structured water, observed in the reaction of the neutral (pH-independent) hydrolysis 132, 331 and in other processes involving water as a reagent [34], may be of great significance for the action of enzymes.…”

mentioning

confidence: 99%

Micellar enzymology

Martínek

Levashov

Klyachko

et al. 1986

European Journal of Biochemistry

547

248

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Experimental approaches to modelling the enzymatic function of biological membranes are discussed. Emphasis is given to pseudohomogeneous systems such as proteolipid complexes and enzymes in organic solvents; the latter are solubilized with phospholipids or synthetic surfactants. Methods for producing and studying such micellar systems are considered. The key research problems of micellar enzymology are formulated and its relation to enzyme membranology is discussed. Finally, the new potentialities are noted of applied enzymology (biotechnology) offered by application of a colloidal solution of water in organic solvents as a microheterogeneous medium for enzymatic reactions.Until now the development of molecular enzymology has been mainly directed to studying free enzymes [l -41. In other words, the most valuable experiments aimed at elucidating the structure of catalytic centers and the physico-chemical mechanisms of biocatalysis were successful only with the enzymes isolated from the living cells in quite a pure form. However, such 'pure' experiments, as was noted time and again [5], naturally raise the question as to whether the enzyme properties observed in vitro can be correlated adequately with the conditions of its functioning in vivo. Such a doubt is quite equitable since it became clear [6 -91 that the subcellular structure and the compartmentalization of enzymes play the most important role in metabolism regulation.Thus, the essence of the contradiction is that in vitro studies of enzymes are usually conducted in water (buffer). However, in the living cell, enzymes mostly act on or near the 'water/ organic medium' interface. For instance, many enzymes, if not the majority, are located on the surface of biological membranes or inside them [lo-161. Other enzymes function in mobile complexes with macromolecular components of the cell, e.g. with proteins or polysaccharides [14 -161. Generally speaking, the boundary between 'bound' and 'diffusion-free' enzymes is rather conventional, and such a classification is more methodical (depending on the ease of the enzyme isolation) than functional (the enzyme localization in the cell) [16]. The problem is that many of the enzymes bind to the membrane surface loosely and the degree of their binding depends on the concentration of metabolites [14-191. The physiological state of the cell determines not only the adsorption of some enzymes but their possible translocation through membranes [20,21]. In the adsorbed state in vivo (on the enterocyte brushborder) extracellular enzymes were found as well, such as proteases of the digestive tract, namely trypsin and a-chymotrypsin [22, 231, which up to now have remained model subjects of the classical 'in-water' enzymology.Finally, a few words about the medium in which diffusionfree enzymes function in the cell (for a review see [24]). It is not very clear why macromolecules (immunoglobulins and albumin) injected into the living cell diffuse so slowly (as in a 60% sucrose solution) [25]. The comparison of the diffusion rat...

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“…It is widely agreed that water adjacent to solid surfaces shows modified properties induced by an orienting effect extending from the first adsorbed and immobilized molecular layer [1][2][3][4][5][6][7]. Unfortunately, there is still a large disagreement in literature about the thickness of the boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Repulsion Phenomena in Thin Layers of Alcoholic Solutions of Tetrabutylammonium Iodide

Peschel¹,

Belouschek²

1980

Zeitschrift Für Naturforschung A

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The structural disjoining pressure of methyl-, ethyl-, n-propyl, and n-butyl alcohol was determined in thin layers between highly smooth rutile surfaces when tetrabutylammonium iodide was added. The a verage thickness of the oriented solvation layers per interface turned out to be largest for methyl alcohol (about 1.5 nm) and decreases like the disjoining pressure when passing to the related alcohols with longer chain lengths. Tetrabutylammonium iodide clearly reduces the thickness of the boundary layer with increasing concentration.

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Structure and Properties of Water at Biological Interfaces

Cited by 58 publications

References 258 publications

Glycerolipid and Fatty Acid Changes in Eastern White Pine Chloroplast Lamellae during the Onset of Winter

Glycerolipid and Fatty Acid Changes in Eastern White Pine Chloroplast Lamellae during the Onset of Winter

Micellar enzymology

Repulsion Phenomena in Thin Layers of Alcoholic Solutions of Tetrabutylammonium Iodide

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