Mixed monolayers of dipalmitoylglycerophosphocholine,distearoylglycerophosphocholine and 1-palmitoylglycerol

Mixed monolayer systems of dipalmitoylglycerophosphocholine (DPPC)-distearoylglycerophosphocholine (DSPC), palmitoylglycerol-DPPC, and palmitoylglycerol-DSPC have been investigated by a previously described thermodynamic treatment. The surface pressures of these systems were measured at various compositions and temperatures. The two-dimensional phase diagrams and the apparent molar entropy and energy changes were evaluated. It was found that the phase diagrams of the DPPC-DSPC, palmitoylglycerol-DSPC and palmitoylglycerol-DPPC systems are all of different types. According to our phase diagram classification, DPPC-DSPC, palmitoylglycerol-DSPC, and palmitoylglycerol-DPPC systems exhibited a modified cigar type, a eutectic type, and a negative azeotropic type, respectively.     

Synthesis of carboxyphospholipids

The chemical synthesis of dialkylphospholipids containing a carboxyl group is described. This carboxyl group forms amides with substances containing free amino groups or certain protective groups.     

Relaxation in LE-LC transition of fatty acid monolayers

The break point observed on fatty acid isotherms corresponds to a transition between two two-dimensional phases, since it is clearly distinct from the collapse. But the transformation from the liquid expanded phase to the liquid condensed phase is slow and relaxations with characteristic times have been observed. Most of the isotherms published so far should be considered with caution since the barrier speed generally used is much greater than the relaxation rate we obtain. Hence, at least in the break point neighbourhood, they are not true equilibrium isotherms.     

Mixed monolayer studies of 12-hydroxyoctadecanoic acid and its esters

Mixed monolayers of two bipolar/bipolar systems have been studied and the results are compared with those obtained from similar monopolar/monopolar systems. DL-12-Hydroxyoctadecanoic acid, methyl DL-12-hydroxyoctadecanoate, and ethyl DL-12-hydroxyoctadecanoate were used as the bipolar substances in this paper. The surface pressure-area/molecule isotherms of both the DL-12-hydroxyoctadecanoic acid/methyl DL-12-hydroxyoctadecanoate system and the methyl DL-12-hydroxyoctadecanoate/ethyl DL-12-hydroxyoctadecanoate system were measured at a variety of compositions and temperatures. Taking advantage of the thermodynamic threatment which has been formulated by Motomura, the two-dimensional phase diagrams and the apparent molar entrophy, enthalpy and energy changes were evaluated for both systems. The DL-12-hydroxyoctadecanoic acid/ethyl DL-12-hydroxyoctadecanoate system exhibited a deformed cigar type diagram while the methyl DL-12-hydroxyoctadecanoate/ethyl DL-12-hydroxoctadecanoate system formed a normal cigar type diagram. The transition thermodynamic quantities of both the DL-12-hydroxyoctadecanoic acid/ethyl DL-12-hydroxoctadecanoate system and the methyl DL-12-hydroxyoctadecanoate/ethyl DL-12-hydroxyoctadecanoate system were respectively much larger than those of similar monopolar/monopolar systems: hexadecanoic acid/ethyl hexadecanoate and ethyl hexadecanoate/ethyl heptadecanoate.     

游离脂肪酸受体蛋白研究进展

游离脂肪酸不仅是人和动物体的一种重要能量来源,也是一种重要的信号分子。最近研究表明,游离脂肪酸受体蛋白在维持机体内的葡萄糖稳衡、脂肪形成、白细胞功能等生理过程中都有重要的作用,对于调控人或动物的营养代谢及疾病发生具有重要生理意义。     

Effect of ciprofibrate on the activation and oxidation of very long chain fatty acids

The effect of ciprofibrate, a hypolipidemic drug, was examined in the metabolism of palmitic (C_16:0) and lignoceric (C_24:0) acids in rat liver. Ciprofibrate is a peroxisomal proliferating drug which increases the number of peroxisomes. The palmitoyl-CoA ligase activity in peroxisomes, mitochondria and microsomes from ciprofibrate treated liver was 3.2, 1.9 and 1.5-fold higher respectively and the activity for oxidation of palmitic acid in peroxisomes and mitochondria was 8.5 and 2.3-fold higher respectively. Similarly, ciprofibrate had a higher effect on the metabolism of lignoceric acid. Treatment with ciprofibrate increased lignoceroyl-CoA ligase activity in peroxisomes, mitochondria and microsomes by 5.3, 3.3 and 2.3-fold respectively and that of oxidation of lignoceric acid was increased in peroxisomes and mitochondria by 13.4 and 2.3-fold respectively. The peroxisomal rates of oxidation of palmitic acid (8.5-fold) and lignoceric acid (13.4-fold) were increased to a different degree by ciprofibrate treatment. This differential effect of ciprofibrate suggests that different enzymes may be responsible for the oxidation of fatty acids of different chain length, at least at one or more step(s) of the peroxisomal fatty acid -oxidation pathway.     

Interrelationships between two-dimensional phase diagrams and mean molecular area-mole fraction curves in mixed monolayers

Both two-dimensional phase diagrams and mean molecular area (A)—mole fraction(x₂^π) curves have been investigated for various types of mixed monolayer systems. Two-dimensional phase diagram analysis and the behavior of A−x₂^π curves were found to be in good agreement with each other. From this result it was concluded that we should consider both phase diagrams and A−x₂^π curves of a mixed monolayer system in order to understand the behavior of the A−x₂^π curves.     

Production of dicarboxylic acids from novel unsaturated fatty acids by laccase-catalyzed oxidative cleavage

The establishment of renewable biofuel and chemical production is desirable because of global warming and the exhaustion of petroleum reserves. Sebacic acid (decanedioic acid), the material of 6,10-nylon, is produced from ricinoleic acid, a carbon-neutral material, but the process is not eco-friendly because of its energy requirements. Laccase-catalyzing oxidative cleavage of fatty acid was applied to the production of dicarboxylic acids using hydroxy and oxo fatty acids involved in the saturation metabolism of unsaturated fatty acids in Lactobacillus plantarum as substrates. Hydroxy or oxo fatty acids with a functional group near the carbon–carbon double bond were cleaved at the carbon–carbon double bond, hydroxy group, or carbonyl group by laccase and transformed into dicarboxylic acids. After 8 h, 0.58 mM of sebacic acid was produced from 1.6 mM of 10-oxo-cis-12,cis-15-octadecadienoic acid (αKetoA) with a conversion rate of 35% (mol/mol). This laccase-catalyzed enzymatic process is a promising method to produce dicarboxylic acids from biomass-derived fatty acids.     

Interaction of fatty acids,acyl-CoA derivatives and retinoids with microsomal membranes: effect of cytosolic proteins

This paper reviews characteristics of microsomal membrane structure; long chain fatty acids, acyl CoA derivatives, retinoids and the microsomal formation of acyl CoA derivatives and retinyl esters. It is analyzed how the movement of these molecules at the intracellular level is affected by their respective binding proteins (Fatty acid binding protein, acyl CoA binding protein and cellular retinol binding protein). Studies with model systems using these hydrophobic ligands and the lipid-binding or transfer proteins are also described. This topic is of interest especially because in the esterification of retinol the three substrates and the three binding proteins may interact. (Mol Cell Biochem20: 89–94, 1993)Abbreviations FABP(s) Fatty Acid Binding Protein(s) - CRBP Cellular Retinol Binding Protein - ACBP Acyl-CoA-Binding Protein     

Biocatalytic acylation of carbohydrates with fatty acids from palm fatty acid distillates

Palm fatty acid distillates (PFAD) are by-products of the palm oil refining process. Their use as the source of fatty acids, mainly palmitate, for the biocatalytic synthesis of carbohydrate fatty acid esters was investigated. Esters could be prepared in high yields from unmodified acyl donors and non-activated free fatty acids obtained from PFAD with an immobilized Candida antarctica lipase preparation. Acetone was found as a compatible non-toxic solvent, which gave the highest conversion yields in a heterogeneous reaction system without the complete solubilization of the sugars. Glucose, fructose, and other acyl acceptors could be employed for an ester synthesis with PFAD. The synthesis of glucose palmitate was optimized with regard to the water activity of the reaction mixture, the reaction temperature, and the enzyme concentration. The ester was obtained with 76% yield from glucose and PFAD after reaction for 74 h with 150 U ml⁻¹ immobilized lipase at 40°C in acetone.     

Measurement of plasma pristanic, phytanic and very long chain fatty acids by liquid chromatography-electrospray tandem mass spectrometry for the diagnosis of peroxisomal disorders

High pressure liquid chromatography with a narrow bore C8 column has been used to separate pristanic, phytanic and very long chain fatty acids, important in the diagnosis of peroxisomal disorders, for their accurate isotope dilution quantification by tandem mass spectrometry. The fatty acids, isolated from plasma, were analysed as trimethylaminoethyl ester (quaternary ammonium) derivatives. Analysis time was 2.5 h and sample requirement was 10 microl of plasma. Good agreement with GC-MS methods for the levels of pristanic and phytanic acids, C26:0/C22:0 and C24:0/C22:0 ratios were obtained for 12 plasma samples from peroxisomal disorder patients and a set of controls.     

Biosynthesis of very long chain monounsaturated fatty acids by subcellular fractions of developing seeds

Subcellular fractions from developing seeds of mustard (Sinapis alba), honesty (Lunaria annua) and nasturtium (Tropaeolum majus) synthesize very long chain cis (n−9) monounsaturated fatty acids, e.g. gadoleic (20:1), erucic (22:1) and nervonic (24:1) acid, from oleoyl-CoA and malonyl-CoA by condensation reactions. The particulate 2000 × g and 15 000 × g fractions exhibit considerably higher elongase activities compared to the microsomal or oil body fractions, whereas the soluble (150 000 × g supernatant) fraction is devoid of such activities.     

Depsidones and fatty acids of Parmelia stygia

One Russian sample of the lichen Parmelia stygia has yielded fumarprotocetraric acid, while a second contained the same compound accompanied by colensoinic, lobaric, caperatic and norcaperatic acids.     

Inhibitory effect of medium-chain-length fatty acids on synthesis of polyhydroxyalkanoates from volatile fatty acids by Ralstonia eutropha

Medium-chain-length fatty acids, such as nonanoic (9:0) and octanoic (8:0) acids, are more toxic to Ralstonia eutropha than volatile fatty acids such as acetic, propionic and butyric acids. Nonanoic acid was degraded to acetic and propionic acids via -oxidation by Ralstonia eutropha for cell growth and synthesis of polyhydroxyalkanoates (PHAs). In a mixture of the fatty acids, utilization of nonanoic acid was depressed by acetic and propionic acids, and vice versa. The PHA accumulation from the volatile fatty acids was decreased from 53% (w/w) of dry cell mass to 23% due to the nonanoic acid. Similar phenomena were also observed with octanoic acid and its metabolic intermediates, acetic and butyric acids.     

A comparison of heart and liver fatty acid-binding proteins: interactions with fatty acids and possible functional differences studied with fluorescent fatty acid analogues

Summary Fatty acid-binding proteins (FABP) are distinct but related gene products which are found in many mammalian cell types. They are generally present in high abundance, and are found in those tissues where free fatty acid (ffa) flux is high. The function(s) of FABP is unknown. Also not known is whether all FABP function similarly in their respective cell types, or whether different FABP have unique functions. The purpose of these studies was to assess whether different members of the FABP family exhibit different structural and functional properties. Two fluorescent analogues of ffa were used to compare the liver (L-FABP) and heart (H-FABP) binding proteins. The propionic acid derivative of diphenylhexatriene (PADPH) was used to examine the physical properties of the ffa binding site on L- and H-FABP, as well as the relative distribution of ffa between FABP and membranes. An anthroyloxy-derivative of palmitic acid, 2AP, was used to monitor the transfer kinetics of ffa from liver or heart FABP to acceptor membranes, using a resonance energy transfer assay. The results demonstrate that the ffa binding sites of both FABP are hydrophobic in nature, although the L-FABP site is more nonpolar than the H-FABP site. Equilibration of PADPH between L-FABP and phosphatidylcholine (PC) bilayers resulted in a molar partition preference of > 20: 1, L-FABP : PC. Similar studies with H-FABP resulted in a PADPH partition preference of only 3:1, H-FABP : PC. Finally, the transfer of 2AP from H-FABP to acceptor membranes was found to be 50-fold faster than transfer from L-FABP. These studies demonstrate that important structural and functional differences exist between different members of the FABP family, and therefore imply that the roles of different FABP may be unique.Abbreviations FABP Fatty Acid-Binding Protein - L-FABP Liver FABP - H-FABP Heart FABP - SUV Small Unilamellar Vesicle - PADPH 3-[p-(6-Phenyl)-1,3,5-Hexatrienyl]-phenylpropionic acid - 2AP 2-(9-Anthroyloxy)Palmitic acid - Q Quantum yield - _F Fluorescence lifetime     

Nature of DNA-bound fatty acids in Pseudomonas aurantiaca

The existence of Pseudomonas aurantiaca DNA-bound fatty acids and lipids is presented in this work. The isolation of DNA was carried out by two different procedures, namely, phenol and detergent-based phenol isolation in order to prove the presence of DNA-bound lipids. The lipid content of DNA is expressed in terms of fatty acid profile. A high level of 16:0, 18:0 and 18:1 is characteristic for tightly bound DNA lipids. On the other hand, the fatty acids such as 14:1, iso14:0 and iso16:0 are found in trace amounts only in DNA lipid fraction, but these fatty acids are not found in the whole-cell lipids. Absolutely no 3-hydroxy fatty acids were found in DNA lipids. However, both C16 and C18 species represent the main fatty acids of whole-cell and DNA-bound lipids. The presence of DNA-bound lipids even under tough treatment of DNA allows to conclude that these lipids represent a special pool among cellular lipids.     

Anti-HCV activities of selective polyunsaturated fatty acids

HCV infection can lead to chronic infectious hepatitis disease with serious sequelae. Interferon-alpha, or its PEGylated form, plus ribavirin is the only treatment option to combat HCV. Alternative and more effective therapy is needed due to the severe side effects and unsatisfactory curing rate of the current therapy. In this study, we found that several polyunsaturated fatty acids (PUFAs) including arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) are able to exert anti-HCV activities using an HCV subgenomic RNA replicon system. The EC(50) (50% effective concentration to inhibit HCV replication) of AA was 4microM that falls in the range of physiologically relevant concentration. At 100microM, alpha-linolenic acid, gamma-linolenic, and linoleic acid only reduced HCV RNA levels slightly and saturated fatty acids including oleic acid, myristic acid, palmitic acid, and steric acid had no inhibitory activities toward HCV replication. When AA was combined with IFN-alpha, strong synergistic anti-HCV effect was observed as revealed by an isobologram analysis. It will be important to determine whether PUFAs can provide synergistic antiviral effects when given as food supplements during IFN-based anti-HCV therapy. Further elucidation of the exact anti-HCV mechanism caused by AA, DHA, and EPA may lead to the development of agents with potent activity against HCV or related viruses.     

The presence of odd-chain fatty acids in Drosophila phospholipids

ABSTRACT

Most fatty acids in phospholipids and other lipid species carry an even number of carbon atoms. Also odd-chain fatty acids (OCFAs), such as C15:0 and C17:0, are widespread throughout the living organism. However, the qualitative and quantitative profiles of OCFAs-containing lipids in living organisms remain unclear. Here, we show that OCFAs are present in Drosophila phosphatidylcholine (PC) and phosphatidylethanolamine (PE) and that their level increases in accordance with progression of growth. Furthermore, we found that food-derived propionic acid/propanoic acid (C3:0) is utilized for production of OCFA-containing PC and PE. This study provides the basis for understanding in vivo function of OCFA-containing phospholipids in development and lipid homeostasis.     

Long-chain fatty acid transport in bacteria andyeast. Paradigms for defining the mechanism underlying this protein-mediated process

Protein-mediated transport of exogenous long-chain fatty acids across the membrane has been defined in a number of different systems. Central to understanding the mechanism underlying this process is the development of the appropriate experimental systems which can be manipulated using the tools of molecular genetics. Escherichia coli and Saccharomyces cerevisiae are ideally suited as model systems to study this process in that both [1] exhibit saturable long-chain fatty acid transport at low ligand concentration; [2] have specific membrane-bound and membrane-associated proteins that are components of the transport apparatus; and [3] can be easily manipulated using the tools of molecular genetics. In E. coli, this process requires the outer membrane-bound fatty acid transport protein FadL and the inner membrane associated fatty acyl CoA synthetase (FACS). FadL appears to represent a substrate specific channel for long-chain fatty acids while FACS activates these compounds to CoA thioesters thereby rendering this process unidirectional. This process requires both ATP generated from either substrate-level or oxidative phosphorylation and the proton electrochemical gradient across the inner membrane. In S. cerevisiae, the process of long-chain fatty acid transport requires at least the membrane-bound protein Fat1p. Exogenously supplied fatty acids are activated by the fatty acyl CoA synthetases Faa1p and Faa4p but unlike the case in E. coli, there is not a tight linkage between transport and activation. Studies evaluating the growth parameters in the presence of long-chain fatty acids and long-chain fatty acid transport profiles of a fat1 strain support the hypothesis that Fat1p is required for optimal levels of long-chain fatty acid transport.     

Trans fatty acids in hydrogenated fat inhibited the synthesis of the polyunsaturated fatty acids in the phospholipid of arterial cells

Our hypothesis that the trans fatty acids in hydrogenated fat inhibited the synthesis of polyunsaturated fatty acids in the phospholipid of arterial cells was tested with five groups each with six pregnant porcine fed from d 35 of gestation and during lactation. The basal diet contained 2% corn oil (control). The other four diets included the control + 10% butter or 10% hydrogenated fat plus two levels of Mg. Plasma, milk and aortic phospholipid fatty acids, phospholipid composition and calcium content of the aorta from the piglets were determined. At 48 +/- 2 d of age, the aorta phospholipid of piglets from porcine fed hydrogenated fat contained a significantly higher concentration of linoleic acid, less arachidonic acid, and less long chain polyunsaturated fatty acid (PUFA) than did piglets from porcine fed either butterfat or the control diet. Mg had no effect. These changes in composition in piglets from porcine fed hydrogenated fat indicate that trans fat inhibits the metabolic conversion of linoleic acid to arachidonic acid and to other n-6 PUFA. The aortic calcium content data showed a significant interaction of calcium concentration with age. We concluded: 1) that dietary trans fat perturbed essential fatty acid (EFA) metabolism which led to changes in the phospholipid fatty acid composition in the aorta, the target tissue of atherogenesis, 2) this inhibition of EFA to PUFA by the isomeric fatty acids in hydrogenated fat is a risk factor in the development of coronary heart disease.