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1.
Determination of positional distribution of short-chain fatty acids in bovine milk fat on chiral columns 总被引:4,自引:0,他引:4
Yutaka Itabashi John J. Myher Arnis Kuksis 《Journal of the American Oil Chemists' Society》1993,70(12):1177-1181
The positional distribution of acetic and butyric acids in bovine milk fat triacylglycerols was determined by chiral-phase
high-performance liquid chromatography (HPLC) of the derived diacylglycerols. Enriched fractions of acetic and butyric acid-containing
triacylglycerols were isolated by normal-phase thin-layer chromatography (TLC) from a molecular distillate of butter oil,
and they were fully hydrogenated. Mixedsn-1,2(2,3)- andX-1,3-diacylglycerols of short- and long-chainlength, which were generated by partial Grignard degradation of the hydrogenated
triacylglycerols, were isolated by borate-TLC. The enantiomericsn-1,2-andsn-2,3-diacylglycerols and theX-1,3-diacylglycerols as their 3,5-dinitrophenylurethanes were resolved by HPLC on chiral columns. Both acetic and butyric
acids were exclusively associated with thesn- 2,3- andX-1,3-diacylglycerols of short and long chainlength. These results establish the presence of acetic and butyric acids in thesn-3-position of bovine milk fat triacylglycerols. Other short-and medium-chainlength acids were found in progressively increasing
proportions also in thesn-1- andsn-2-positions. 相似文献
2.
This study reports a facile identification of the molecular species of enantiomeric diacylglycerols by combining chiral phase
high-performance liquid chromatography with positive chemical ionization mass spectrometry. For this purpose the 3,5-dinitrophenylurethane
(DNPU) derivatives ofsn-1,2(2,3)-diacylglycerols are separated on an (R+)-naphthylethylamine polymer column (25 cm × 0.46 cm ID) using an isocratic
solvent system made up of hexane/dichloroethane/acetonitrile (85∶10∶5, by vol) or isooctane/tert-butyl methyl ether/acetonitrile/isopropanol (80∶10∶5∶5, by vol). About 1% of the column effluent (1 mL/min) was admitted
to a quadrupole mass spectrometer (Hewlett-Packard, Palo Alto, CA)via direct liquid inlet interface, and positive chemical ionization spectra were recorded over the range of 200–900 mass units.
The DNPU derivatives of diacylglycerols yield characteristic [M-DNPU]+ and [RCO+74]+ ions for each diacylglycerol species from which the molecular weight and exact pairing of fatty acids can be unequivocally
obtained. The characteristic ions appear to be generated in nearly correct mass proportions as indicated by preliminary quantitative
comparisons.
The abbreviations 14∶0, 16∶1, 18∶2, etc. represent normal chain fatty acids of 14, 16, 18, etc. acyl carbons and 0, 1, 2,
etc. double bonds, respectively; 16∶0–18∶1, etc. represent diacylglycerols containing 16∶0 and 18∶1 fatty acids of unspecified
positional distribution;sn indicates stereospecific numbering of glycerol carbons;sn-1,2-diacylglycerols andsn-2,3-diacylglycerols are enantiomeric diacylglycerols of unspecified fatty acid composition;rac-1,2-diacylglycerols are racemic diacylglycerols representing equal amounts ofsn-1,2-andsn-2,3-enantiomers;sn-1,2(2,3)-diacylglycerols are a mixture ofsn-1,2-andsn-2,3-diacylglycerols of unspecified proportion of enantiomers and unspecified fatty acid compisition and positional distribution;
X-1,3-diacylglycerols are diacylglycerols of unspecified fatty acid composition and reverse isomer content. 相似文献
3.
A method is described for the determination of molecular species of oil triacylglycerols. The method is based on the analytical
separation of the enantiomericsn-1,2-andsn-2,3-diacylglycerols, derived from triacylglycerols, by high-performance liquid-chromatography (HPLC) on a chiral column containing
N-(R)-1-(α-naphthyl)ethylaminocarbonyl-(S)-valinecarbonyl-(S)-valine as stationary phase. Model triacyl-glycerol molecules
comprising three known fatty acids were isolated from peanut oil and cottonseed oil by a combination of argentation-TLC and
reversed-phase HPLC and submitted to partial chemical deacylation. The derivedsn-1,2(2,3)-diacylglycerols were analyzed and fractionated as 3,5-dinitrophenyl urethane derivatives by reversed-phase HPLC
according to chainlength and unsaturation. From thesn-1,2(2,3)-diacylglycerol composition and the diacylglycerolsn-1,2-andsn-2,3-enantiomer composition, the individual molecular species of four peanut oil triacylglycerols and one cottonseed oil triacylglycerol
were identified and quantitated. The method can be applied to triacylglycerols of any other oil or fat. 相似文献
4.
P. Damianl F. Santinelli M. S. Simonetti M. Castellini M. Rosi 《Journal of the American Oil Chemists' Society》1994,71(10):1157-1162
Two methods for stereospecific analysis of triacylglycerols are compared. Procedure A, based on stereospecific phosphorylation
ofsn-1,2-diacylglycerols to phosphatidic acids, and procedure B, based on separation of the diastereomeric 1,2(2,3)-diacylglycerol
urethane derivatives by high-performance liquid chromatography on silica, were applied to olive oil triacyl-sn-glycerols. Statistical evaluation of the results showed good reproducibility, and Student'st-test indicates no statistical differences between the two considered procedures, although some small differences were observed
and discussed. Fifteen samples of extra-virgin olive oil, produced in the same region (Umbria, Italy), were analyzed with
the two considered procedures. 相似文献
5.
Toru Ota Yasunosuke Kawabata Yasuhiro Ando 《Journal of the American Oil Chemists' Society》1994,71(5):475-478
This paper presents the positional distribution of very long-chain fatty acids, 24∶6(n−3), in triacyl-sn-glycerols (TG) of flathead flounder (Hippoglossoides dubius). Each of the liver and flesh TGs was subjected to the stereospecific analysis. The liver TGs contained 24∶6(n−3) at concentrations
of 1.5, 1.2 and 1.7 mole % in thesn-1,sn-2 andsn-3 positions, respectively, and the flesh TGs had 9.0, 7.8 and 7.1 mole % in thesn-1,sn-2 andsn-3 positions, respectively. This fatty acid was distributed almost evenly among the three positions of the TGs. No preference
for thesn-2 position was observed in contrast to the general tendency for the distribution of longer-chain polyunsaturated fatty acids,
such as 22∶6(n−3), 22∶5(n−3) and 20∶5(n−3). There was essentially no difference in the positional distributions of the liver
and flesh TGs. The results obtained in this study give new fundamental information to the investigation of very long-chain
fatty acids. 相似文献
6.
The positional distribution of fatty acids has been determined for the milk triacylglycerols of the Antarctic fur seal,Arctocephalus gazella. Of particular interest was the positional distribution of the polyunsaturated n−3 fatty acids in milk triacylglycerols (TG).
In adipocytes of pinnipeds, TG are synthesized with the n−3 fatty acids primarily in thesn-1,3 positions. To determine the positional distribution, extracts of enzymatically digested lipids were separated by thin-layer
chromatography, and the constituent fatty acids were separated and quantified by gas-liquid chromatography. Monoenoic and
saturated fatty acids comprised over 75% of the total, the ratio of monoenoic to saturated fatty acids being 2∶1. The percent
content of the long-chain n−3 fatty acids, 20∶5, 22∶5 and 22∶6, ranged between 15–20%. The positional analyses revealed that
at thesn-2 position of milk TG, saturated fatty acids were in excess (57%), and the content of n−3 fatty acids was less than 5%. More
than 80% of the n−3 fatty acids in milk were located in thesn-1,3 positions. The data indicate that in pinnipeds TG are synthesized in the mammary gland and adipose tissue with fatty
acids having similar positional distributions. 相似文献
7.
Human milk triacylgycerols (TAG) were analyzed by tandem mass spectrometry. The SIMPLEX method and a simple linear model were
used to interpret the distribution of fatty acids between thesn-2 andsn-1,3 positions in 24 major molecular weight groups of TAG. The number of regio-isomeric pairs of TAG varied between 3 and
18 in each of these groups. Hexadecanoic (16∶0), tetradecanoic (14∶0) and dodecanoic acids (12∶0) typically occupied thesn-2 position in TAG containing less than 54 acyl carbons, whereas long-chain C18 and C20 acids were predominantly located at
the primary positions. The positions of the three fatty acids within a TAG molecule were shown to depend on the fatty acid
combination. The maximum of 12∶0 in thesn-2 position appeared at acyl carbon number (ACN) 48, the maxima of 14∶0 were at ACN 44 and ACN 50, and for 16∶0 at ACN 46
and 52. 相似文献
8.
William W. Christie Boryana Nikolova-Damyanova Päivi Laakso Bengt Herslof 《Journal of the American Oil Chemists' Society》1991,68(10):695-701
The compositions of positionssn-1, 2 and 3 of triacylglycerols can be determined by partial hydrolysis with ethyl magnesium bromide, derivatization of the
total products with (S)-(+)-1-(1-naphthyl)ethyl isocyanate and isolation of the diacyl-sn-glycerol urethane derivatives by chromatography on solid-phase extraction columns containing an octadecylsilyl phase. The
diastereomericsn-1,2-and 2,3-diacylglycerol derivatives are separated by high-performance liquid chromatography on silica for determination
of their fatty acids by gas chromatography. Each step in the process has been evaluated rigorously. The compositions of all
three positions can be calculated with good accuracy from the analyses of these compounds and that of the total triacylglycerols.
Although the 1,3-sn-diacylglycerol derivatives can also be isolated easily, they do not give reliable results for the composition of positionsn-2 because acyl migration occurs during their generation. The stereospecific analysis procedure has been applied to some plant
and animal triacyl-sn-glycerols of commercial and scientific interest, containing predominantly C16 and C18 fatty acids,i.e. safflower, sunflower, olive and palm oils, tallow, egg and rat adipose tissue. The method is not at present suited to the
analysis of more complex triacylglycerols, such as milk fat or fish oils, and problems associated with these are discussed. 相似文献
9.
The biosynthesis of diacylglycerols from 2-monoacylglycerols and free fatty acids was examined in evert sacs of rat intestinal
mucosa. By means of alternate labeling of the monoacylglycerols and fatty acids, and conventional stereo-specific analysis,
it was shown that the main products of synthesis were thesn-1,2-diacylglycerols (53–63%), butsn-2,3-diacylglycerols (37–47%) were also formed in significant amounts. The total yield and proportions of the isomeric diacylglycerols
recovered appeared to vary with the nature of the monoacylglycerol and the complexity of the free fatty acid mixture supplied. 相似文献
10.
T. H. Sanders 《Journal of the American Oil Chemists' Society》1980,57(1):12-15
Oils from three varieties of mature peanuts and from one variety at seven physiological maturity stages were extracted with
petroleum ether and fractionated into lipid classes. The fatty acid composition of the whole oils and fractions were then
determined. The fractions from the Starr variety generally contained more 16:0 and 18:2 and less 18:1 than those from the
Florunner and Florigiant varieties. Long chain fatty acids (C20–C24) were generally more predominant in thesn-1,3-diacylglycerol fraction than in other fractions, and only traces of long chain acids were found in the sn-1,2(2,3)-di-acylglycerol
fraction. An unusual compound associated with thesn- 1,3-diacylglycerol fraction was detected by GLC. Fatty acid compositions of classes in the different maturity stages showed
that, generally, the concentration of 18:1 increased and that the concentrations of all other fatty acids decreased with maturity. 相似文献
11.
Detailed investigation was made of the triacylglycerol structure of three varieties of peanut oils of varying atherogenic
activity. By means of chromatographic and stereospecific analyses, it was shown that all the oils had markedly nonrandom enantiomeric
structures with the long chain saturated fatty acids (C20−C24) confined exclusively to thesn-3-position, whereas the palmitic and oleic acids were distributed about equally between thesn-1-andsn-3-positions, with the linoleic acid being found preferentially in thesn-2-position. On the basis of detailed studies of the molecular species of the separatesn-1,2-,sn-2,3- andsn-1,3-diacylglycerol moieties, it was concluded that the fatty acids in the three positions of the glycerol molecule are combined
with each other solely on the basis of their relative molar concentrations. As a result, it was possible to calculate the
composition of the molecular species of the peanut oil triacylglycerols (including the content of the enantiomers and the
reverse isomers) by means of the 1-random 2-random 3-random distribution. In general, the three peanut oils possessed triacylglycerol
structures which where closely similar to that derived earlier for a commercial peanut oil of North American origin. Since
their oil has exhibited a high degree of atherogenic potential, it was anticipated that the present oils would likewise be
atherogenic, which has been confirmed by biological testing. However, there are certain differences in the triacylglycerol
structures among these oils, which can be correlated with the variations in their atherogenic activity. The major differences
reside in the linoleic/oleic acid ratios in the triacylglycerols, especially in thesn-2-position, and in the proportions in which these acids are combined with the long chain fatty acids. On the basis of the
characteristic structures identified in the earlier analyzed atherogenic peanut oil, the peanut oil of South American origin
would be judged to possess the greatest atherogenic potential and this has been borne out by biological testing. 相似文献
12.
Rapid and practical separations of 1,2-and 2,3-diacyl-and dialkyl-sn-glycerol enantimers as their 3,5-dinitrophenylurethane derivatives were carried out by normal-phase high performance liquid
chromatography on a chiral stationary phase, N-(R)-1-(α-naphthyl)ethylaminocarbonyl-(S)-valine chemically bonded to γ-aminopropyl silanized silica. Complete separations of the racemates into enantiomers were
achieved for both of the diacyl-and dialkylglycerols within 10 min using a stainless steel column (25 cm long) packed with
the 5-μ particles, an isocratic elution with a mixture of hexane/ethylene dichloride/ethanol as a mobile phase and a UV detector.
Thesn-1,2-enantiomers were eluted ahead of the correspondingsn-2,3-enantiomers. Satisfactory separation of thesn-1,3-diacylglycerols from the corresponding enantiomers and the separation of the homologues differing in acyl and alkyl groups
were also observed. The formations of hydrogen bonding and charge transfer complex between the urethane derivatives and the
stationary phase may contribute to the enantiomer separations. 相似文献
13.
Diacylglycerols have been separated as their (S)-(+)-or (R)-(−)-1-(1-naphthyl)ethyl urethanes by high performance liquid chromatography (HPLC) on a column of silica gel with 0.5% 2-propanol
in hexane as the mobile phase. The elution order of components derivatized with the (S)-form of the reagent was 1,3-, followed by 1,2-, and finally 2,3-diacyl-sn-glycerols. The elution order of 1,2- and 2,3-diastereomers was reversed when the (R)-form of 1-(1-naphthyl)ethyl isocyanate was used for derivatization. Single-acid 1,2- and 2,3-diastereomers were separated
to the baseline with a resolution factor from 5.2–5.7, and the resolution factor between 1,3- and 1,2- or 2,3-diacyl-sn-glycerol derivatives was more than 23. Molecular species of single-acid diacylglycerol derivatives were separated in the
sequence 18∶1<18∶0<18∶2<16.0.
In order to assess this methodology as part of a procedure for the stereospecific analysis of triacyl-sn-glycerols, we prepared diacyl-rac-glycerols from maize oil, evening primrose oil and egg yolk triacylglycerols by partial hydrolysis with ethyl magnesium bromide.
The 1,3-, 1,2- and 2,3-diacyl-sn-glycerols as (S)-(+)-1-(1-naphthyl)ethyl urethanes were isolated and their fatty acid compositions were determined. Although this only permitted
an indirect determination of the compositions of positionssn-1,-2 and-3, it was sufficient to indicate the potential of the methodology because results comparable to those published
earlier were achieved. 相似文献
14.
Milk triglycerides from the platypus were subjected to fatty acid and stereospecific analysis to determine the positional
distribution of fatty acids in the triglycerides. Of the major fatty acids, 12∶0 was preferentially esterified at thesn-3 position, 14∶0 and 16∶0 were selectively associated with thesn-2 position, and 18∶0 was located predominantly at thesn-1 position. The unsaturated fatty acids, 14∶1, 16∶1, 18∶1, 18∶2 and 18∶3, were preferentially esterified at thesn-3 position. The fatty acid distribution pattern of the platypus, a monotreme, is similar to that of marsupials and eutherians
but is in contrast to the only other extant monotreme, the echidna. 相似文献
15.
The enantiomeric composition of the monounsaturated triacylglycerols (TG) from cocoa butter was estimated. The monounsaturated
TG were separated into three fractions by reversed-phase high-performance liquid chromatography (HPLC), and each fraction
was subjected to the stereospecific analysis with chiral-phase HPLC. The results indicated that the major TG consisted of
equal amounts of 1-stearoyl-2-oleoyl-3-palmitoyl-sn-glycerol (SOP-sn-TG) and POS-sn-TG (47 mol%), 1,3-distearoyl-2-oleoyl-glycerol (SOS-TG) (33 mol%), and POP-TG (19 mol%). The contents of SOP-sn-TG and POS-sn-TG are 1.30 times that of the POP-TG content, and the SOS-TG content is 1.302 times that of the POP-TG content. The term “priority factor” is proposed for the ratio of the stearoyl group/palmitoyl group,
1:30 at thesn-1 andsn-3 or 1(3)-position. It shows a distinct specificity for particular fatty acids or their Coenzyme A esters in random esterification
at each position of the glycerol moiety in the biosynthesis of cocoa butter TG. 相似文献
16.
Lipase-catalyzed interesterification of butterfat was carried out in a cosurfactant-free microemulsion system containing mixtures
of Span 60 and Tween 60 (ICI Specialty Chemicals Altemix Inc., Brantford, Ontario, Canada) as surfactants. Four commercial
lipases were used—Lipozyme 10,000L (Novo Nordisk, Copenhagen, Denmark) and N, D and MPA (Amano Pharmaceutical Co. Ltd., Nagoya,
Japan). Stereospecific analyses of fractionated selected high-molecular weight triacylglycerols were performed by enzymatic
deacylation with commercial pancreatic lipase, random generation ofrac-1,2-diacylglycerols by Grignard degradation, synthesis ofrac-phosphatidylcholines and a stereospecific release ofsn-1,2 diacylglycerols by phospholipase A2. The results showed that the hydrolytic affinity of commercial lipases demonstrated an acyl-group specificity toward lower-molecular
weight fatty acids C4–C14∶0. Stereospecific analyses of fatty acids of interesterified selected triacylglycerols of butterfat
catalyzed by lipase N demonstrated a 46% increase in the proportion of C18∶1cis Δ9 at thesn-2 position, whereas those catalyzed by lipases MAP, D and Lipozyme 10,000L were enriched with C16∶0 at the same position
by 21, 35 and 41%, respectively. 相似文献
17.
Huang Yung-Sheng Lin Xiaorong Redden Peter R. Horrobin David F. 《Journal of the American Oil Chemists' Society》1995,72(6):625-631
The present study compared thein vitro hydrolysis of two 18:3n-6-rich oils—evening primrose oil (EPO) and borage oil (BO)—and different synthetic 18:3n-6-containing
triacylglycerols (TG). Incubation of EPO and BO with pancreatic lipase lipolyzed 18:3n-6 from the TG species. The rate of
lipolysis of TG species containing two or three molecules of 18:3n-6, which comprised 36% of total 18:3n-6 in BO and only
7% in EPO, was significantly slower than those containing only one molecule of 18:3n-6. This was found especially in those
with two molecules of linoleic acid, which constituted 20% of total 18:3n-6 in BO, whereas over 80% were present in EPO. In
a separate study, various synthetic 18:3n-6-containing TG were also subjected toin vitro hydrolysis by pancreatic lipase. Results showed that release of 18:3n-6 from thesn-1/sn-3 positions was significantly slower when two other stereospecific positions in the same TG molecule were occupied by either
palmitic acid (16:0) or monounsaturated (18:1 and 20:1) fatty acids than when occupied by 18:2n-6. The rate of hydrolysis
ofsn-2-γ-linolenyl-sn-1(3)-diacylglycerol to formsn-2-mono-γ-linolenyl glycerol was also significantly slower when both thesn-1 andsn-3 positions in TG molecules were occupied by either saturated fatty acids (16:0 and 18:0) or long-chain monounsaturated fatty
acids than when occupied by 18:2n-6. These findings suggest that the stereospecific position of 18:3n-6 in TG molecules and
the constituent of its neighboring fatty acids modulated availability of 18:3n-6 from 18:3n-6-containing TG or 18:3n-6-rich
oils. 相似文献
18.
Determination of lipase specificity 总被引:1,自引:0,他引:1
Specificity of lipases is controlled by the molecular properties of the enzyme, structure of the substrate and factors affecting
binding of the enzyme to the substrate. Types of specificity are as follows. I. Substrate: (a) different rates of lipolysis
of TG, DG, and MG by the same enzyme; (b) separate enzymes from the same source for TG, DG and MG. II. Positional: (a) primary
esters; (b) secondary esters; and (c) all three esters or nonspecific hydrolysis. III. Fatty acid, preference for similar
fatty acids. IV. Stereospecificity: faster hydrolysis of one primarysn ester as compared to the other. V. Combinations of I–IV. Lipases with these specificities are: Ia, pancreatic; Ib, postheparin
plasma. IIa, pancreatic; IIb,Geotrichum candidum, for fatty acids withcis-9-unsaturation, and IIc,Candida cylindracea. III,G. candidum for unsaturates. IV.sn-1, postheparin plasma andsn-3 human and rat lingual lipases. V. Rat lingual lipase. Methods for determination involve digestion of natural fats of known
structure and synthetic acylglycerols followed by analysis of the lipolysis products. All of the types of specificity have
been detected with use of synthetic acylglycerols. Detection of stereospecificity requires enantiomeric acylglycerols which
are difficult to synthesize, so other methods have been developed. These involve the generation of 1,2-(2,3) DG and resolution
of the enantiomers. Trioleoylglycerol or racemic TG can be used as substrates. If the lipase is stereospecific, then either
thesn-1,2- or 2,3-enantiomer will predominate. The relative amounts of the enantiomers can be determined by measurement of specific
rotation, and nuclear magnetic resonance spectra. The DG can also be separated by conversion to phospholipids and hydrolysis
with phospholipases A-2 or C. Applications of these procedures are discussed and data on the specificity of various lipases
presented.
Scientific Contribution No. 988, Storrs Agricultural Experiment Station, University of Connecticut, Storrs, CT 06268.
Trioleoylglycerol is 18∶1−18∶1−18∶1, etc. 1,2-dioleoyl-3-palmitoyl-sn-glycerol issn-18∶1−18∶1−16∶0, with thesn-1 ester to the left. If the TG is racemic,rac is omitted. 相似文献
19.
Effects of different medium-chain fatty acids on intestinal absorption of structured triacylglycerols 总被引:3,自引:0,他引:3
To study the effect of the chain length of medium-chain fatty acids on the intestinal absorption of long-chain fatty acids,
we examined the lymphatic transport of fat following administration of five purified structured triacylglycerols (STAG) containing
different medium-chain fatty acids in the sn-1, 3 positions and long-chain fatty acids in the sn-2 position in a rat model. Significant amounts of medium-chain fatty acids were found in lymph samples after intragastric
administration of 1,3-dioctanoyl-2-linoleyl-sn-glycerol (8∶0/18∶2/8∶0), 1,3-didecanoyl-2-linoleyl-sn-glycerol, and 1,3-didodecanoyl-2-linoleyl-sn-glycerol. The accumulated lymphatic transport of medium-chain fatty acids increased with increasing carbon chain length.
The recoveries of caprylic acid (8∶0), capric acid (10∶0), and lauric acid (12∶0) were 7.3±0.9, 26.3±2.4, and 81.7±6.9%, respectively.
No significant differences were observed for the maximal intestinal absorption of linoleic acid (18∶2n−6) when the chain length
of medium-chain fatty acids at the primary positions was varied, and the absorption of 18∶2 and oleic acid (18∶1) from 8∶0/18∶2/8∶0
and 1,3-dioctanoyl-2-oleyl-sn-glycerol was similar. We conclude that the chain length of the medium-chain fatty acids in the primary positions of STAG
does not affect the maximal intestinal absorption of long-chain fatty acids in the sn-2 position in the applied rat model, whereas the distribution of fatty acids between the lymphatics and the portal vein reflects
the chain length of the fatty acids.
Presented in part at the 3rd ISSFAL Conference, Lyon, France, June 1–5, 1998. 相似文献
20.
David C. Taylor Nikolaus Weber Lawrence R. Hogge Edward W. Underhill M. Keith Pomeroy 《Journal of the American Oil Chemists' Society》1992,69(4):355-358
Homogenates of microspore-derived embryos of rape (Brassica napus L.) incubated with [1-14C]erucoyl-CoA and 1,2-dierucoylglycerol are able to assemble trierucoyl-glycerol (trierucin). In addition, radioactive triacylglycerols
are formed by transferring [1-14C]-erucoyl moieties to endogenous lipid precursors. Stereospecific analysis of radioactive triacylglycerols revealed that
labeled erucoyl moieties had been incorporated exclusively into thesn-1,3 positions with more than 95% of radioactivity in thesn-3 position. No incorporation of labeled erucic acid into thesn-2 position has been observed. All data agree with the involvement of 1,2-diacylglycerol acyltransferase (E.C. 2.3.1.20),
which utilized 1,2-dierucoylglycerol as well as endogenous 1,2-diacylglycerols as acceptors of erucoyl moieties. This result
is of particular interest for the genetic modification of rape and other Cruciferae for producing trierucin in their seed
oils.
NRCC No. 33513. 相似文献