Long-chain Fatty Acid Esters Research Articles

Sucrose Esters of Long-Chain Fatty Acids

Sucrose Esters of Long-Chain Fatty Acids

Allyl esters of crambe‐derived long‐chain fatty acids and their polymers

AbstractAllyl esters of erucic, brassidic, behenic, oleo‐erucic, and stearo‐behenic acids, prepared by refluxing benzene solutions of the acids with excess allyl alcohol in the presence of p‐toluenesulfonic acid monohydrate, polymerize smoothly in the presence of 5 wt. % t‐butyl perbenzoate at 120°C for 24 hr. Polymerization of the unsaturated acid esters involves a large portion (ca. 84%) of allylic and a small portion (ca. 26%) of ethylenic bonds. The products, saturated and unsaturated, have a degree of polymerization between 6 and 10 and are soluble in typical polymer solvents. Crystallinity, judged by thermal analysis, decreased with increased cis unsaturation. The oligomers melted between −30°C and 59°C and started decomposing at 200°C.

Acylation of Cotton Fabric with Isopropenyl Stearatel

Cellulose fabric is rapidly made water-repellent by direct acylation with isopropenyl stearate, which is representative of isopropenyl esters of long-chain fatty acids. The esterification produced a material with minor change in tensile strength. Acylation by isopropenyl stearate (IPS) was accomplished by transfer of reagent to cloth followed by heat- curing in an acid-catalyzed reaction. The low levels of catalyst (0.05% by weight of IPS), short curing periods (7-60 s), and low heating temperatures (~180°C) provided conditions for chemical incorporation of a fatty acid at low levels of substitution (DS < 0.001).

Micro Determination of a Low Degree of Stearoyl Substitution in Partially-Stearoylated Cotton Fabric

A rapid, direct, sensitive method of analysis of cellulose esters of long-chain fatty acids has been developed. The method consists of saponification with propanolic potassium hydroxide, neutralization by passage through a microcolumn contain ing an acid-coated solid support, and glc analysis of the liberated fatty acids. The method affords determination of the stearic constituent as low as one mg stearoyl group per gram of cloth.

Ovipositional behavior ofBracon mellitor Say, a parasitoid of the boll weevil (Anthonomus grandis Boheman) III. Isolation and identification of natural releasers of ovipositor probing

The chemical cues in the frass of larvae of the boll weevil,Anthonomus grandis Boheman, that elicit an ovipositional response in females ofBracon mellitor Say were isolated by a combination of column, thin-layer, and gas-liquid chromatography. Derivatization, analytical tests, and mass spectrometry were used to identify the biologically active materials as long-chain fatty acid esters of cholesterol. Bioassays with natural and synthetic cholesteryl esters were used to confirm activity. The activity of the cholesteryl esters was also confirmed by using females that had not been previously exposed to hosts.

Cholesterol esterase produced by Streptomyces lavendulae.

Cholesterol esterase was purified from the culture filtrate of Streptomyces lavendulae by a procedure involving precipitation with ammonium sulfate and acetone, gel filtration on Sepharose CL-4B, and rechromatography on Sepharose CL-4B after treatment of Triton X-100. The purified enzyme was detected as a single band by polyacrylamide disc electrophoresis, while one main band and three minor bands were observed by SDS gel electrophoresis. The molecular weight of the main band was 29000. The enzyme was inhibited by Hg2+, Ag+ and DFP. Long-chain fatty acid esters of cholesterol were hydrolyzed preferentially and pH optimum was 6.0. This enzyme could be used to the determination of total serum cholesterol with cholesterol oxidase from Streptomyces violascens.

Lipids from conidia of Erysiphe graminis tritici (powdery mildew)

Lipids of conidia of Erysiphe graminis tritici were analysed by thin-layer chromatography, gas chromatography and mass spectrometry. Saturated and unsaturated hydrocarbons (such as C 17 , C 19 , C 21:1 and C 25:1 and naturally occurring methyl esters of long-chain fatty acids (C 17 to C 25 ) were detected. The free fatty acids ranged from C 12 to C 24 and unsaturated fatty acids such as C 22:1 and C 24:1 were present. The conidial walls had different appearances when processed with scanning electron microscopy, freeze-etching and thin-sectioning procedures. Lipid bodies were not present in lipid extracted conidia and spore walls of lipid extracted conidia characteristically had electron dense tripartite layers and clumped together.

Studies on sterol metabolism by microorganisms. V. Purification and properties of cholesterol esterase from Pseudomonas fluorescens.

Cholesterol ester hydrolase (EC 3. 1. 1. 13) was purified about 10 times from the culture supernatant of Pseudomonas fluorescens ATCC 21156 by a procedure involving fractionations with acetone and ammonium sulfate, chromatography on hydroxylapatite, gel filtration on Sephadex G-100, and separation into two isoenzymes, I and II, by isoelectric focusing. The purified enzyme from the Sephadex G-100 fraction sedimented as a single peak on ultracentrifugation. The isoenzymes I and II showed isoelectric points of pH 3.8 and 4.9, respectively. They both had an apparent molecular weight of about 129, 000, hydrolyzed preferentially long-chain fatty acid esters of cholesterol, and exhibited a pH optimum at 7.3 with cholesterol linoleate as substrate. The Km values of I and II for cholesterol linoleate were 3.86×10-5 M and 1.43×10-4 M, respectively. The cholesterol esterase activity was remarkably stimulated when Triton X-100 was used to prepare the miscellar aqueous substrate, and further increase in activity was demonstrated by the addition of cholic acid to the miscellar system.

Preparation and thin-layer chromatography of bromo derivatives of unsaturated fatty acid esters : A simple and rapid procedure for fatty acid analysis

Bromo-addition products of unsaturated long-chain fatty acid esters have been prepared and chromatographed on thin layers of unmodified silica gel. The polarity of these derivatives was found to be directly related to the number of double bonds of the parent fatty acis from which they were derived. This has been made the basis of a simple method for assessing the relative proportions of the main fatty acid classes in a mixture.

Z protein in hepatic uptake and esterification of long-chain fatty acids.

Fatty acids radioactivity was bound to Z protein in liver after administration of['3H]oleate to rats or to a perfused rat liver preparation. Pretreatment withflavaspidic acid (340 mumol/kg), a potent inhibitor of fatty acid binding to hepatic Zprotein in vitri, effectively reduced oleate radioactivity bound to Z by 90.2 plusor minus 4.3% and 85.0 plus or minus 6.2% in the intact rat and perfused liver, respectively. In spite of this effect, pretreatment of rats with flavaspidic acid did notalter plasma clearance, hepatic uptake, and esterification of ['3H]oleate. In contrast, in the perfused liver preparation, infusion of flavaspidic acid (340 mumol/kg)or bromosulphalein (360 mumol/kg) increased uptake of ['3H]oleate at least twofold,and oleate esterification was decreased by 15-30%. These results suggest that the binding of long-chain fatty acids to Z protein is not an obligatory step in their uptakeby the liver and that Z protein may be involved in fatty acid esterification.

Chemical composition of angelica root oil.

The volatile constituents of angelica root separated by extraction with etherpentane and by extraction with alcohol-water were investigated by means of glass capillary and preparative gas chromatography, IR, UV, NMR and mass spectrometry. 16 monoterpene hydrocarbons, 13 sesquiterpene hydrocarbons, 12 monoterpene alcohols, 4 oxygenated sesquiterpenes, 11 esters, 3 lactones, 7 aliphatic carbonyl compounds and 4 aromatics were identified. Twenty additional compounds identified were present only in the alcoholic sample. These consisted of ethyl ethers of monoterpene alcohols, ethyl esters of long-chain fatty acids, and acetals. The relative proportion of many compounds was found to depend on the method used to isolate the essential oil.

The carboxylesterases/amidases of mammalian liver and their possible significance.

AbstractWith regard to the acyl moiety, carboxylesterases preferentially split esters of short-chain carboxylic esters. With most carboxylesterases the maximum of the reaction rate is found at an acyl chain length of C3 to C624,77,170,303 (see Section 5.4). However, there are some reports of carboxylesterases acting on medium- and long-chain fatty acid esters as well.143,189,252,253

Studies on the lipase of Chromobacterium viscosum. IV. Substrate specificity of a low molecular weight lipase.

Substrate specificity of lipase B (low molecular weight) of Chromobacterium viscosum was studied. It was suggested that the apparent substrate specificity for emulsions of single triglyceride was affected by the physical state of the emulsion. At a lower temperature, triglycerides of medium-chain fatty acids were good substrates, while at higher temperatures, triglycerides of long-chain fatty acids became better substrates. It was concluded from the data on hydrolysis of methyl esters of fatty acid and the mixture of a series of single triglyceride that lipase B had a specificity to long-chain and unsaturated fatty acid esters, but the esters of stearic acid were not good substrates. Further, it was suggested that the mixture of a series of single triglycerides was more appropriate than the single substrates for studies on the substrate specificity of lipase. Lipase B was capable of hydrolyzing the fatty acid ester bonds at the 2-position of triglycerides as well as the 1- and 3-positions at the same rate.

Dünnschichtchromatographische analyse radioaktiv markierter insektenpheromone: Metaboliten des [ 3H]bombykol

Thin-layer chromatographic analysis of radioactively labelled insect pheromones. Metabolites of [ 3H]bombykol Highly labelled [ 3H]bombykol is extensively metabolized on the antennae of the silkmoth Bombyx mori into free fatty acids and fatty acid esters. The metabolites of the acid fraction consist of one long-chain unsaturated fatty acid of the type of 10- trans, 12- cis-hexadecadienoic acid ( ca. 90%) and of one short-chain unidentified fatty acid ( ca. 10%). The neutral fraction contains except unchanged [ 3H]bombykol at least six long-chain 3H-labelled fatty acid esters.

Mechanism of fat malabsorption in rats infected with Nippostrongylus brasiliensis.

Long-chain fatty acid absorption in rats with a jejunal lesion similar to that which is found in adult coeliac disease has been studied. Neither changes in the solubility of the fatty acid in the intestinal lumen nor histological abnormalities of the villous epithelium accounted for the malabsorptive state. Evidence was obtained from studies in vivo of a disturbance in the intramucosal esterification of long-chain fatty acid. Assay of the activity of the microsomal enzymes responsible for the conversion of fatty acid to triglyceride revealed that this pathway was defective in the parasitized animals.

The action of pure pig pancreatic lipase upon esters of long-chain fatty acids and short-chain primary alcohols

Equimolecular mixtures of esters of long-chain fatty acids and short-chain primary alcohols are hydrolysed by pure porcine pancreatic lipase, and the composition of the acyl chains in the liberated fatty acids is compared to that of initial esters mixtures. This gives the relative lipolysis rates of esters in which the alkyl groups are different. Methyl esters are cleaved by lipase 5 times faster than ethyl esters. The relative hydrolysis rates remain rather slow for esters of C 3 and C 4 alcohols; they increase abruptly for esters of n-hexyl alcohol, which are, in fact, cleaved faster than methyl esters. The results are compared to those that had been previously observed with rat pancreatic juice; they are discussed in relation to a possible enzyme specificity and to the orientation of ester molecules at an oil-water interface.

Fatty Acid Ethyl Esters of Rhizopus arrhizus

Gas chromatographic and mass spectrometric analyses on selected lipid fractions revealed for the first time the presence of ethyl esters of long-chain fatty acids as biological products. Ethyl esters of oleic, palmitic, and stearic acids were detected in relative concentrations of 21.2, 2.4, and 1.5 percent, respectively, of the total methyl and ethyl ester fraction. Both saturated and unsaturated ethyl esters contain pronounced mass spectral fragments at a mass-to-charge ratio of 88.

Lipid Synthesis by Lung Subcellular Particles

The lung mitochondria-rich fraction has been reported to be the most active subcellular fraction in synthesizing long-chain acids from acetate. Experiments on esterification of long-chain fatty acids indicated that this is a function mainly of the microsomal fraction and that mitochondrial activity was 50% of the microsomal. Both subcellular fractions incorporated 14C from palmitic acid mainly into lecithin and triglycerides. Experiments on the incorporation of 14C from nitrogenous bases or methyl donors indicated that choline is incorporated into lecithin mainly by a pathway which is stimulated by the presence of Ca++ in the incubation medium and phosphorylcholine by the cytidine diphosphate-choline pathway. Both pathways are common to microsomal and mitochondrial fractions but the microsomal fraction appears to be more active. Both lung particulate fractions therefore are able to synthesize lecithin from its subcomponents and by transmethylation reactions.

The enzymic deacylation of phospholipids and galactolipids in plants. Purification and properties of a lipolytic acyl-hydrolase from potato tubers

An enzyme preparation that catalyses the deacylation of mono- and di-acyl phospholipids, galactosyl diglycerides, mono- and di-glycerides has been partially purified from potato tubers. The preparation also hydrolyses methyl and p-nitrophenyl esters and acts preferentially on esters of long-chain fatty acids. Triglycerides, wax esters and sterol esters are not hydrolysed. The same enzyme preparation catalyses acyl transfer reactions in the presence of alcohols and also catalyses the synthesis of wax esters from long-chain alcohols and free fatty acids. Gel filtration, DEAE-cellulose chromatography and free-flow electrophoresis failed to achieve any separation of the acyl-hydrolase activities towards different classes of acyl lipids (phosphatidylcholine, monogalactosyl diglyceride, mono-olein, methyl palmitate and p-nitrophenyl palmitate) or any separation of these activities from a major protein component. For each class of lipid the acyl-hydrolase activity was subject to substrate inhibition, was inhibited by relatively high concentrations of di-isopropyl phosphorofluoridate and the pH responses were changed by Triton X-100. The hydrolysis of phosphatidylcholine was stimulated 30-40-fold by Triton X-100. The specific activities of the potato enzyme with galactolipids were at least 70 times higher than those reported for a homogeneous galactolipase enzyme purified from runner bean leaves. The possibility that a single lipolytic acyl-hydrolase enzyme is responsible for the deacylation of several classes of acyl lipid is discussed.

Analysis of sucrose esters of long-chain fatty acids on Sephadex LH-20

The sucrose esters of long-chain fatty acids were separated into their components by gel chromatography on Sephadex LH-20. The conditions for gel chromatography were investigated and adjusted as follows: column, 2.0 × 230 cm; column temperature, 50°; developing solvent, DMF; flow rate, 60 ml/h; sample size, 50 mg. Mono-, di-, tri- and higher sucrose esters, sucrose and methyl esters of fatty acids were separated. Reproducibility was satisfactory. The time required for a single determination was about 12 h.