Lipid physical properties

Gibbs, A.G. (1998). The role of lipid physical properties in lipid barriers. Amer. Zool. 38 268-279. 

October (Volume 1, No.5) - Biosynthesis of C5 - CgQ Terpenoids (J.R. Hanson), Fatty Acids (F.D. Gunstone), Lipids - Physical Properties (D.P, C ulnn), Llpids-Chemlcal Properties (W.W. Christie), Diterpenoids (J.R. Hanson), Unusual Long-chain compounds from Mycobacteria and Related Organisms, (D.E. Minnlkln). 

Chemists and biochemists And it convenient to divide the principal organic substances present m cells into four mam groups carbohydrates proteins nucleic acids and lipids Structural differences separate carbo hydrates from proteins and both of these are structurally distinct from nucleic acids Lipids on the other hand are characterized by a physical property their solubility m nonpolar solvents rather than by their structure In this chapter we have examined lipid molecules that share a common biosynthetic origin m that all their carbons are derived from acetic acid (acetate) The form m which acetate occurs m many of these processes is a thioester called acetyl coenzyme A... 

The lipids found in biological systems are either hydrophobic (containing only nonpolar groups) or amphipathic, which means they possess both polar and nonpolar groups. The hydrophobic nature of lipid molecules allows membranes to act as effective barriers to more polar molecules. In this chapter, we discuss the chemical and physical properties of the various classes of lipid molecules. The following chapter considers membranes, whose properties depend intimately on their lipid constituents. 

Lipids are naturally occurring organic molecules that have limited solubility in water and can be isolated from organisms by extraction with nonpolar organic solvents. Fats, oils, waxes, many vitamins and hormones, and most nonprotein cell-meznbrane components are examples. Note that this definition differs from the sort used for carbohydrates and proteins in that lipids are defined by a physical property (solubility) rather than by structure. Of the many kinds of lipids, we ll be concerned in this chapter only with a few triacvlglycerols, eicosanoids, terpenoids, and steroids. 

Cullis PR, Fenske DB, Fiope MJ Physical properties and functional roles of lipids in membranes. In Biochemistry of Lipids, Lipoproteins and Membranes. Vance DE, Vance JE (editors). Elsevier, 1996. 

The lipid molecule is the main constituent of biological cell membranes. In aqueous solutions amphiphilic lipid molecules form self-assembled structures such as bilayer vesicles, inverse hexagonal and multi-lamellar patterns, and so on. Among these lipid assemblies, construction of the lipid bilayer on a solid substrate has long attracted much attention due to the many possibilities it presents for scientific and practical applications [4]. Use of an artificial lipid bilayer often gives insight into important aspects ofbiological cell membranes [5-7]. The wealth of functionality of this artificial structure is the result of its own chemical and physical properties, for example, two-dimensional fluidity, bio-compatibility, elasticity, and rich chemical composition. 

Further progress may derive from a more accurate definition of the chemical and physical properties of the humic substances present at the rhizosphere and how they interact with the root-cell apoplast and the plasma membrane. An interaction with the plasma membrane H -ATPase has already been observed however this master enzyme may not be the sole molecular target of humic compounds. Both lipids and proteins (e.g., carriers) could be involved in the regulation of ion uptake. It therefore seems necessary to investigate the action of humic compounds with molecular approaches in order to understand the regulatory aspects of the process and therefore estimate the importance of these molecules as modulators of the root-soil interaction. 

Gruszecki, W.I. and K. Strzalka. 2005. Carotenoids as modulators of lipid membrane physical properties. Biochim. Biophys. Acta 1740 108-115. 

Subczynski, W. K., J. Widomska, and J. B. Feix. 2009. Physical properties of lipid bilayers from EPR spin labeling and their influence on chemical reactions in a membrane environment. Free Radic. Biol. Med., 46, 707-718. 

Subczynski, W. K. and A. Wisniewska. 1998. Effects of P-carotene on physical properties of lipid membranes-comparison with effects of polar carotenoids. Curr. Top. Biophys. 22 44—51. 

Widomska, J., M. Raguz, J. Dillon, E. R. Gaillard, and W. K. Subczynski. 2007. Physical properties of the lipid bilayer membrane made of calf lens lipids EPR spin labeling studies. Biochim. Biophys. Acta 1768 1454-1465. 

Subczynskil, W.K. and Wisniewska, A. (2000) Physical properties of lipid bilayer membranes relevance to membrane biological functions. Acta Biochimica Polonica, 47 (3), 613-625. 

We thank Dr. M. Hirano at Toray Research Center, Kamakura for providing us with the purified PS II. We also thank Dr. H. Minamikawa for the synthesis of Maln(Phyt)2 and Dr. K. Kawasaki for the FFEM experiments. This work was performed as a part of a R D project of AIST (subject Physical properties of membrane protein/lipid assemblies) and of International Joint Research Program FY 2001-2002 supported by NEDO. 

Biophysical analysis of biomolecules like proteins, nucleic acids, or lipids utilizes intrinsic physical properties of the observed molecule itself or of an associated reporter molecule, which reflect information about structural characteristics, interactions, or reactions of the subject observed. In most cases the analysis (and the labels introduced) only interferes slightly with the interaction of interest and does not induce significant changes in the properties of the reactants. 

Rabinovich A. L. and Ripatti, P. O. (1991). On the conformational, physical properties and functions of polyunsaturated acyl chains, Biochim. Biophys. Acta-Lipid. Metahol, 1085, 53-62. 

V. VonTschamer and H. M. McConnell, Physical properties of lipid monolayers on alkylated planar glass surfaces, Biophys. J. 36, 421-427 (1981). 

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