Hydrophobic fatty acid

A typical biomembrane consists largely of amphiphilic lipids with small hydrophilic head groups and long hydrophobic fatty acid tails. These amphiphiles are insoluble in water (<10 ° mol L ) and capable of self-organization into uitrathin bilaycr lipid membranes (BLMs). Until 1977 only natural lipids, in particular phospholipids like lecithins, were believed to form spherical and related vesicular membrane structures. Intricate interactions of the head groups were supposed to be necessary for the self-organization of several ten thousands of... 

Bistline and Stirton compared the CMC values of ester sulfonates with cyclic ester groups [54]. The phenyl esters have higher values than benzyl and cyclohexyl esters. The influence of the structure of the ester group decreases with increasing chain length of the hydrophobic fatty acid group. The cyclic esters of a-sulfostearic acid, for example, have nearly the same CMC values. 

Phospholipids are the most important of these liposomal constituents. Being the major component of cell membranes, phospholipids are composed of a hydrophobic, fatty acid tail, and a hydrophilic head group. The amphipathic nature of these molecules is the primary force that drives the spontaneous formation of bilayers in aqueous solution and holds the vesicles together. 

Glycolipids are carbohydrate-containing molecules, usually of sphingosine derivation, possessing a hydrophobic, fatty acid tail that embeds them into membrane bilayers. The hydrophilic... 

In the development of the protein-fatty acid condensates it was possible to combine the renewable resources fatty acids (from vegetable oil) and protein, which can be obtained from both animal waste (leather) as well as from many plants, to construct a surfactant structure with a hydrophobic (fatty acid) and a hydrophilic (protein) part (Fig. 4.12). This was carried out by reacting protein hydrolysate with fatty acid chloride under Schotten-Baumann conditions using water as solvent. Products are obtained that have an excellent skin compatibility and, additionally, a good cleaning effect (particularly on the skin) and, in combination with other surfactants, lead to an increase in performance. For instance, even small additions of the acylated protein hydrolysate improve the skin compatibility. An... 

Similiar to albomycin and ferrichromes, the linear tripeptide of A -hydroxy-A -acetyl-ornithine can be used as the simplest chiral template for artificial siderophores. It can be used alone as a tripeptide like for 80, can be conjugated to a hydrophobic fatty acid 81132 pj. p j.j longer peptide 82, 83, and 85. ... 

Our present ideas about the nature of biological membranes, which are so fundamental to all biochemical processes, are based on the Singer-Nicholson mosaic model. This model of the membrane is based on a phospholipid bilayer that is, however, asymmetrical. In the outside monolayer, phosphatidylcholine (lecithin) predominates, whereas the inner monolayer on the cytoplasmic side is rich in a mixture of phos-phatidylethanolamine, phosphatidylserine, and phosphatidylinositol. Cholesterol molecules are also inserted into the bilayer, with their 3-hydroxyl group pointed toward the aqueous side. The hydrophobic fatty acid tails and the steran skeleton of cholesterol... 

Structure of phosphatidic acid, a phosphoglyceride. A saturated fatty acid is esterified at carbon 1 of the glycerol, and a cA-unsaturated fatty acid at carbon 2. The cluster of polar and charged oxygens makes the head-group hydrophilic, in marked contrast to the hydrophobic fatty acid chains. 

Lipid bilayers will spontaneously self-assemble in aqueous solution. The major driving force behind this is the hydrophobic effect - the hydrophobic fatty acid chains avoid coming into contact with the water molecules. Once... 

The detailed structure of membranes is not uniform in terran life (Figure 2.12). Membrane bilayers in bacteria arise from supramolecular organization of phospholipids, with hydrophobic fatty acids attached to a variety of polar head groups by ester linkages. Eukaryotic membranes also contain phospholipids, but they are distinctive in the inclusion of sterols (such as cholesterol), another class of hydrophobic molecules. 

If an amphiphile, such as lysolecithin, is suspended in water, it forms micelles, whose three-dimensional shape is that of an inverted cone. The basis for this type of assembly is that the hydrophobic fatty acid tails will interact with each other and exclude water from their environment, whereas the hydrophilic phosphocholine section remains in contact with the aqueous environment. If lecithins, cephalins, or cardiolipins are suspended in water, they aggregate into... 

Liposomes are formed by the self-assembly of amphiphilic phospholipids, possessing a hydrophilic, ionised phosphate gronp and a long hydrophobic fatty acid chain, in aqueous solutions. In solution the phospholipid molecnles form a closed bilayer sphere in an attempt to shield their hydro-phobic gronps from the polar aqueons environment while still maintaining contact with the aqneons phase via the hydrophilic phosphate group. The resulting sphere may... 

The structure of a micelle formed from the phospholipid lecithin. The straight lines represent the long hydrophobic fatty acid tails, and the spheres represent the hydrophilic heads of the phospholipid. 

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