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1.
A concentrate of branched chain fatty acids (as methyl esters) was prepared from the triacylglycerols of subcutaneous adipose
tissue lipids of lambs receiving a carbohydrate-rich (cereal) diet. This was accomplished by procedures which allowed the
removal of unsaturated components by peroxidation and straight chain saturated components by urea-adduct formation. The concentrate
was analyzed by high resolution gas chromatography in combination with mass spectrometry and was shown to consist of a complex
mixture of saturated methyl-substituted fatty acids. Methyl substitution occurred on even-numbered carbon atoms (relative
to the carboxyl group) and the chain lengths of the acids ranged from 10 to 18 carbon atoms. Acids with one methyl substituent
in the fatty acyl chain were most abundant; di-, tri- and tetramethyl-substituted acids were also present. The biosynthesis
of these methyl-substituted acids is discussed briefly. 相似文献
2.
A. K. Sen Gupta 《European Journal of Lipid Science and Technology》1972,74(12):693-705
The main aspects of recent research on the occurrence, isolation, structure, biogenesis and metabolism of the methyl branched fatty acids have been reviewed. For the purpose of this work the fatty acids were classified in the following 5 groups: 1. Iso- or anteiso-acids; 2. Branched chain acids with one methyl branching in the middle of the chain; 3. Multiple branched acids with methyl branching on alternate carbon atoms; 4. Multiple branched acids with isoprenoid structure; 5. Mycolic acids. The literature has been covered up to 1969. 相似文献
3.
This present work characterizes the fatty acid constituents of the lipid fraction of royal jelly. Among the organic acids
found after fractionation by thin layer chromatography of the corresponding methyl esters, the following compounds were identified
by combined GC-MS: saturated and unsaturated linear fatty acids, saturated and unsaturated linear and branched dicarboxylic
acids, mono-and dihydroxy acids. The most common characteristic of the organic acids was that most contained 8 or 10 carbon
atoms, whether saturated or unsaturated, linear or branched. 相似文献
4.
2-Substituted 4,4-dimethyloxazolines (DMOX) have been found to be a useful alternative to the commonly used methyl esters
for the localization of unsaturated bounds and other substituents in the fatty chain by mass spectrometry. The powerful directed
fragmentation coupled with good gas chromatographic ability enables the structure elucidation of modified fatty acids in complex
mixtures. Continuing our previous study, 76 out of a total of 86 fatty acids obtained from the preen gland wax of shanghai
duck now have been identified by gas chromatography-mass spectrometry (GC-MS) of their oxazoline derivatives. The identification
was based on the interpretation of the mass spectra and comparison with the spectra and equivalent chain lengths (ECL) of
the corresponding methyl esters. Main components of this lipid mixture are straight chain fatty acids (8.22%), and 2-, 4-or
6-monomethyl branched acids (53.69%), amounting to 61.91% of the total acid fraction. In addition, a large number of dimethyl-substituted
fatty acids (31.4%) also have been found. Typical mass spectra, which are easily recognizable and highly specific for fatty
acids substituted at various positions, are presented and classified according to the structural feature of the chain.
Chemical Modification in Mass Spectrometry 6. For preceding paper in this series, see Ref. 17. 相似文献
5.
The wax material in the secretion of a scale insect,Ceroplastes pseudoceriferus Green was analyzed chemically with special interest to the composition of higher fatty acids and higher alcohols. The wax
consists of 34.2% fatty acids, 27.1% unsaponifiable matter and 29.5% resin acids. The fatty acids were found to be a complex
mixture of 15 normal acids ranging from C8 to C32. Of these, octacosanoic, triacontanoic and dotriacontanoic acids comprise over 30% of the wax. Presence of relatively large
amount of unsaturated fatty acids of the C18 series (2.8% of the wax) is of particular interest.
From the unsaponifiable fraction, only one saturated straight chain aleohol, bexacosanol, was detected (2.7% of the original
wax). The other unsaponifiable matter was considered to be cyclic or branched carbon chain, and consisted of at least 12 to
20 compounds. The resin acid fraction was also found to be a complex mixture of at least 13 to 14 components. 相似文献
6.
Products of Dimerisation Unsaturated Fatty Acids VIII: The Fraction of “Intermediates” Obtained by Dimerisation of Unsaturated Fatty Acids The fraction of “intermediates” which is obtained by dimerisation of unsaturated fatty acid contains straight chain saturated fatty acids with 20-24 carbon atoms as well as methyl branched isomers thereof. The production of these compounds is probably caused by the presence of small amounts of monounsaturated fatty acids with 20-24 carbon atoms in the starting material. The fraction of “intermediates” contains in addition monocarboxylic acids with 36 carbon atoms. These are probably formed after dimerisation by an intramolecular cyclisation reaction under participation of one carboxylic group, followed by hydrogenation of the produced carbonyl group. Finally the formed alcoholic group is eliminated as a water molecule, and the produced double bond is hydrogenated. 相似文献
7.
Degras contains a complex mixture of lipids comprised of branched and normal chain fatty acids, hydroxy acids, sterols, sterol
esters and long chain wax esters. There are no glycerides in degras. This paper is a report on the composition of the branched
and normal chain fatty acids. Preparative techniques of thin-layer chromatography were used to isolate the fatty acids from
the other lipid classes. Gas chromatography was used on three different stationary phase separations of the fatty acid methyl
esters. Identifications of the composition were based on a combination of techniques and known standards.
Authorized for publication on April 20, 1965, as paper No. 3003 in the journal series of The Pennsylvania Agricultural Experiment
Station. 相似文献
8.
Gilles Barnathan Joseph Mirallès Emile M. Gaydou Nicole Boury-Esnault Jean-Michel Kornprobst 《Lipids》1992,27(10):779-784
The fatty acid composition of phospholipids from the Senegalese spongeCinachyrella alloclada was examined. Two new fatty acids not hitherto found in nature, namely 10,13-octadecadienoic acid and 16-tricosenoic acid,
were identified. 8-Hexadecenoic, 13-nonadecenoic and 5,9,13-trimethyltretradecanoic fatty acids were also found for the first
time in sponges. The latter compound (1.4% of the total fatty acid mixture), an isoprenoid fatty acid, accompanies the major
fatty acid 4,8,12-trimethyltridecanoic acid (19.7%). The monomethyl branched fatty acids (22%) identified include 23-methylpentacosanoic
acid (anteiso-26∶0), not previously observed in sponged. The major long-chain fatty acids encountered were the known 17-tetracosenoic
19-heptacosadienoic and 5,9,23-tricontatrienoic acid. Some sixty fatty acids were identified as methyl esters andN-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry. 相似文献
9.
Three isomeric epithio stearic acids have been concentrated as possible minor sulfur-bearing components of unprocessed canola
oil. Chromatographic and mass spectral evidence is presented in support of these novel fatty acid structures, tentatively
identified as isomeric 9, 12; 8, 11; and 7, 10 epithio stearic acids, each with a methyl substituent on the ring.
Presented in part at the AOCS Canadian Section meeting in Guelph, Ontario, October 1986. 相似文献
10.
P. Nuhn 《European Journal of Lipid Science and Technology》1996,98(10):335-338
Analytics and biophysics of branched fatty acids in lipids . Objects of our investigations are long chain fatty acids with methyl groups in different positions and fatty acids with a different length of the sidegroup in α-position. The separation of racemic branched fatty acid methyl esters by gas chromatography on a chiral column depends on the structure of the branched fatty acid. Diastereomeric amides and phosphatidylcholines with α-branched fatty acid residues were separated preparatively. The branched fatty acids were incorporated into 1,2-diacyl-, 1-acyl-2-hexadecyl- and 2-acyl-1-hexadecyl-glycerophosphocholines and characterized by differential scanning calorimetry and X-ray diffraction. 相似文献
11.
Ursula Biermann Jürgen O. Metzger 《European Journal of Lipid Science and Technology》2008,110(9):805-811
Alkyl‐branched fatty compounds are of interest for industrial products in the cosmetics and lubricant areas. In this review, clay‐ and zeolite‐catalyzed isomerizations of unsaturated fatty compounds, especially of oleic acid, are discussed. While clay‐catalyzed reactions give most complex mixtures of dimeric fatty acids and of monomeric so‐called “isostearic acid”, the zeolite‐catalyzed process yields preferentially an isomeric mixture of isostearic acids having the methyl branch on the 8–14 positions of the alkyl chain. Synthetically useful additions of alkyl radicals can only be performed on ω‐unsaturated fatty compounds, whereas perfluoroalkyl iodides were added to fatty compounds with terminal as well as internal double bonds using electron transfer‐initiated radical addition reactions. Electrophilic additions of alkyl carbenium ions generated by decomposition of alkyl chloroformates by ethylaluminum sesquichloride give well‐defined alkyl‐branched oleochemicals with good yields. 相似文献
12.
The hydroxylation activity of the Thr268Ala mutant of P450(BM3) has been shown to occur to varying degrees with small alterations in the structure of a fatty-acid substrate. Ten substrates were investigated, including straight chain, branched chain and cis-cyclopropyl substituted fatty acids with a straight-chain length that varied between 12 and 16 carbon atoms. The efficacy of the hydroxylation activity appeared to be governed by the chain length of the substrate. Substrates possessing 14 to 15 carbons afforded the highest levels of activity, which were comparable with the wild-type enzyme. Outside of this window, straight-chain fatty acids showed reduced activity over the other substrate types. These results provide a cautionary tale concerning the loss of ferryl activity in such cytochrome P450 threonine to alanine mutants, as the nature of the substrate can determine the extent to which hydroxylation chemistry is abolished. 相似文献
13.
Thorsten Hanhoff Sailas Benjamin Torsten Brchers Friedrich Spener 《European Journal of Lipid Science and Technology》2005,107(10):716-729
We observed earlier that phytanic acid activated subtype α of the peroxisome proliferator‐activated receptor (PPAR) via the cytosolic liver‐type fatty acid‐binding protein (L‐FABP). In a further search for minor lipid nutrients that interact with genes, we explored here the potential of branched‐chain fatty acids to serve as agonists for the PPAR subtypes α, β and γ in rodent and human molecular test systems. Beyond chlorophyll‐derived pristanic and phytanic acids, bacteria‐derived iso‐ and anteiso‐fatty acids and avian‐derived ‘uropygial’ fatty acids were tested by transactivation assay. In addition, we studied binding of these fatty acids to recombinantly expressed PPAR ligand binding domains (LBDs) and to L‐FABP by competition with fluorescent parinaric acid. In contrast to single methyl‐branched agonists, multi methyl‐branched fatty acids had high transactivation potentials in either test system; in addition, some agonists of the latter were highly subtype selective. Multi methyl‐branched chain fatty acids were superior activators of human PPARγ, a preference not seen in the murine test system. High‐affinity binding of isoprenoid‐derived pristanic and phytanic acids to PPARγ‐LBD and to L‐FABP was observed, and also of pristanic acid to PPARα‐LBD. Polyketidic uropygial fatty acids bound to PPARγ‐LBD only, though weakly. As both isoprenoid and polyketidic fatty acids showed high activation potentials, it became clear that binding data determined in vitro cannot predict biological activity as determined by transactivation assay. For pristanic acid, however, a signalling path similar to that found for phytanic acid can be concluded. Taken together, multi methyl‐branched fatty acids of the human food chain can affect cellular metabolism through regulating gene expression. 相似文献
14.
The lipophilic components of choline phosphoglycerides and ethanolamine phosphoglycerides obtained from the salt gland of
herring gull and eider duck and from the rectal gland of spiny dogfish were investigated by means of thin-layer chromatography,
gas chromatography, and gas chromatography-mass spectrometry. All phospholipids analyzed were shown to contain small amounts
of plasmalogens, and mainly C16, C18, and C18∶1 aldehyde was detected. The fatty acids were composed of saturated, unsaturated,
straight chain, and branched chain types, ranging between 14–22 carbon atoms. The lipophilic composition of the rectal gland
phospholipids showed a higher degree of unsaturation and the presence of more branched chain fatty acids than that of the
birds, possibly related to body temperature. 相似文献
15.
Ibrahim R. Shimi Nabila A. Maroun Mamdouh Y. Kamel Hemmat H. Ragheb Mohga M. Badran 《Lipids》1974,9(6):368-373
Gas liquid chromatographic analysis of the fatty acid methyl esters from eggs ofDermacentor andersoni Stiles (Ixodidae) revealed the presence of significant quantities (15% total fatty acids) of an unidentified component with a retention time between C18∶3−C22∶0 fatty acids. Smaller amounts of the unidentified component (ca. 5% total fatty acid) also were detected in host rabbit serum. Purified, the unidentified component's methyl ester collected from the tick eggs by preparative gas liquid chromatography was partially identified and characterized by chemical and spectroscopic analyses. The evidence suggests that the unidentified component is a methyl branched C15 tricarboxylic acid containing two vicinal carboxylic acid groups. Biosynthesis of the unidentified component by the tick is under investigation. 相似文献
16.
Fatty acids are the primary natural starting materials for the production of surfactant and detergent molecules. Derived from
vegetable (oil) and animal (fat) triglyceride sources, the fatty acids are linear aliphatic carboxylic acids. Industrial interest
in branched-chain fatty acids is driven by the needs for products with enhanced performance benefits including higher solubility,
ease of handling, better hard water tolerance, and improved oxidative stability. Therefore, catalytic processes have been
developed for the conversion of linear fatty acids to branched ones. High yields of branched acids are obtained from unsaturated
fatty acids over acidic zeolites, particularly those with large pores. Fatty esters also are readily isomerized to branched
ones by means of the same catalyst and process. It is postulated that the isomerization of fatty acids proceeds through three-
and four-membered ring carbocation intermediates formed inside the largepore zeolites. This is supported by evidence of methyl
and ethyl branching in the primary and final products. The total number of carbon atoms in the fatty acid molecule is unchanged.
Surfactants derived from branched fatty acids show favorable physical properties, including a lower viscosity and improved
handling, even as intended performance characteristics are maintained. 相似文献
17.
18.
Helen L. Ngo Robert O. Dunn Eunha Hoh 《European Journal of Lipid Science and Technology》2013,115(6):676-683
Iso‐oleic acid is a mixture of C18‐unsaturated branched‐chain fatty acid isomers with a methyl group on various positions of the alkyl chain, which is the product of the skeletal isomerization reaction of oleic acid and is the intermediate used to make isostearic acid (C18‐saturated branched‐chain fatty acid isomers). Methyl iso‐oleate, a mixture of C18‐unsaturated branched‐chain fatty acid methyl ester isomers, is obtained via acid catalyzed esterification of iso‐oleic acid with methanol. The branched‐chain materials are liquid at room temperature and their “oiliness” property makes them an attractive candidate for the lubricant industry. In this paper, we report characterization of these branched‐chain materials using comprehensive two‐dimensional GC with time‐of‐flight mass spectrometry (GC × GC/TOF‐MS) and their physical and lubricity properties using tribology measurements. 相似文献
19.
Branched-chain fatty acids of perinephric triacylglycerols of semi-feral fallow deer (Dama dama dama) were analyzed by high resolution gas chromatography-mass spectrometry. Of the total fatty acids, 15.50% were Branched-chain
components including 8.96% iso acids, mostly 14-methylpentacanoic acid, 2.85% anteiso acids and 1.73% of other monomethyl-substituted
acids; dimethyl-branched acids with an iso structure (1.05%) and with an anteiso structure (0.18%) were also present. Whereas
the predominant iso acids and methyl-substituted iso acids had chain lengths of 13 and 15 carbon atoms, the anteiso acids
and methyl-substituted anteiso acids had chain lengths of 14 and 16 carbon atoms. Methyl substitution occurred on the even
numbered carbon atoms relative to the carboxyl group. The general composition is also given of the fatty acids comprising
the triacylglycerols of subcutaneous (rump area) and perinephric adipose tissue. 相似文献
20.
以海南产新鲜高种椰为原料,参照国家标准GB/T 14772-93和GB5009.6-85,分别采用索氏抽提法和酸水解法提取新鲜椰肉脂肪酸成分,再经过氢氧化钾碱催化法进行脂肪酸的甲酯化处理后,通过气相色谱/质谱联用技术分析测定脂肪酸的组成。共检出9种脂肪酸成分,主要成分为以月桂酸为主的C6至C18系列饱和脂肪酸。 相似文献