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1.
In this study, the 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine content of human platelets was determined. The distribution of arachidonate among the 1,2-diacyl,
1-O-alkyl-2-acyl, and 1-O-alk-l′-enyl-2-acyl classes of choline- and ethanolamine-containing phosphoglycerides was also assessed. The major platelet
phospholipids were choline-containing phosphoglycerides (38%), ethanolamine-containing phosphoglycerides (25%) and sphingomyelin
(18%), with smaller amounts of phosphatidylserine (11%) and phosphatidylinositol (4%). In addition to the diacyl class, the
choline-linked fraction was found to contain both 1-O-alkyl-2-acyl (10%) and 1-O-alk-l′-enyl-2-acyl (9%) species. The ethanolamine-linked fraction, on the other hand, had an elevated level of the 1-O-alk-l′-enyl-2-acyl (60%) species and a small amount of the 1-O-alkyl-2-acyl component (4%). The major fatty acyl residues found in all classes of the choline and ethanolamine phospholipids
were 16∶0, 18∶0, (Δ9), 18∶2(n−6) and 20∶4(n−6). The 1-O-alk-l and 1-O-alk-l′-enyl fraction of the ethanolamine-linked phospholipids also contained substantial amounts of 22∶4(n−6), 22∶5(n−3)
and 22∶6(n−3) acyl chains. Arachidonate comprised 44% of the acyl residues in thesn-2 position of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine. Corresponding values for the diacyl and 1-O-alk-l′-enyl-2-acyl species were 23% and 25%, respectively, based on all 20∶4(n−6) being linked to thesn-2 position of all classes. In the ethanolamine-linked phosphoglycerides, arachidonate constituted 60%, 20% and 68% of the
acyl groups in thesn-2 position of the 1,2-diacyl, 1-O-alkyl-2-acyl and 1-O-alk-l′-enyl-2-acyl classes, respectively. The content of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine appears sufficient to support the synthesis of platelet activating factor by a deacylation-reacylation
pathway in platelets. Our findings also demonstrate that human platelets contain a significant amount of 1-O-alkyl-2-arachidonyl-sn-glycero-3-phosphocholine that could possibly serve as a precursor of both platelet activating factor and bioactive arachidonate
metabolites. 相似文献
2.
The existence of ether-linked phospholipids, including 1-O-alk-1′-enyl-2-acyl and 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholines and ethanolamines in bonitoEuthynnus pelamis (Linnaeus) white muscle, was investigated by gas chromatography and gas chromatography-mass spectrometry. Chemical ionization
(iso-butane) mass spectrometry of trimethylsilyl ethers derived from the corresponding ether-linked glycerophospholipids proved
effective not only for determining molecular weights but also for structural identification based on the ions [M−R]+, [M−RO]+ and [M+1]+. 1-O-Alk-1′-enyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine accounted for 3.0–6.0% and 3.6–7.6% of the total glycerophospholipids, respectively.
1-O-Alkyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine were also determined for one fish and accounted for 1.4% and 0.6% of the total
glycerophospholipids, respectively. The predominant long chains in thesn-1 position of the glycerol moieties were 16∶0, 18∶0 and 18∶1 in the case of the alkenylacyl and alkylacyl components. Fatty
acid distribution of individual glycerophospholipids was also determined. 相似文献
3.
Molecular species of 1-O-alk-1′-enyl-2-acyl-, 1-O-alkyl-2-acyl-, and 1,2-diacyl-sn-glycero-3-phosphoethanolamine (EPL) andsn-glycero-3-phosphocholine (CPL) of Japanese oysterCrassostrea gigas were analyzed by selectedion monitoring gas chromatography/mass spectrometry using electron impact ionization. The characteristic
fragment ions, [RCH=CH+56]+ due to the alkenyl residue in thesn-1 position and [RCO+74]+ due to the acyl residue in thesn-2 position of alkenylacylglycerols, [R+130]+ due to the alkyl residue in thesn-1 position and [RCO+74]+ due to the acyl residue in thesn-2 position of alkylacylglycerols, [RCO+74]+ due to the acyl residues in thesn-1 and/orsn-2 positions of diacylglycerols, and [M−57]+ being indicative of the corresponding molecular weight, were used for structural assignments.
For alkenylacyl EPL and CPL, 19 and 16 molecular species were determined, respectively. Two molecular species, 18∶0alkenyl-22∶6n−3
and 18∶0-alkenyl-22∶2-non-methylene interrupted diene (NMID), amounted to 53.2% and 47.9%, respectively. The alkylacyl EPL
and CPL consisted of 16 and 20 molecular species, respectively, and the prominent components were 18∶0alkyl-22∶2NMID, 20∶1alkyl-20∶1n−11
(27.4%) and 20∶1alkyl-20∶2NMID (16.3%) in the former, and 16∶0alkyl-20∶5n−3 (23.0%) and 16∶0alkyl-22∶6n−3 (21.6%) in the latter.
For the diacyl EPL and CPL, 14 and 51 molecular species were determined, respectively. The major molecular species were 18∶0–20∶5n−3
(37.4%), 16∶0–20∶5n−3 (14.2%) and 18∶1n−7–22∶2NMID (13.2%) in the former, and 16∶0–20∶5n−3 (33.4%) and 16∶0–22∶6n−3 (22.3%)
in the latter. It was found that there were significant differences in the molecular species between the alkylacyl and diacyl
EPL and the alkylacyl and diacyl CPL; the number of molecular species was larger in CPL than in EPL, while the number of total
carbons and double bonds of the major molecular species were larger in the EPL than in the CPL. Alkenylacyl EPL were similar
to alkenylacyl CPL in molecular species composition. 相似文献
4.
The fatty chain compositions of 1-O-alk-1′-enyl-2-acyl, 1-0-alkyl-2-acyl, and 1,2-diacyl glycerophospholipids of the Japanese oysterCrassostrea gigas (Thunberg) were investigated. Major fatty chains in thesn-1 position of 1-alk-1′-enyl-2-acyl ethanolamine phospholipids (EPL) were 18∶0 (64.7%) and 20∶1 (11.1%). Majorsn-1 chains of alkenylacyl choline phospholipids (CPL) were 18∶0 (63.3%) and 16∶0 (22.2%). In the case of 1-alkyl-2-acyl EPL,
the predominant fatty chains in thesn-1 position were 18∶0 (51.5%), 16∶0 (16.0%) and 20∶1 (12.5%); in the case of 1-alkyl-2-acyl CPL, the majorsn-1 chains were 16∶0 (44.0%) and 14∶0 (23.4%). Saturated fatty chains were predominant in both EPL and CPL. Prominent fatty
acids in thesn-2 position of the alkenylacyl EPL were 22∶6n−3 (29.0%), 20∶5n−3 (19.0%) and 22∶2 NMID (non-methylene interrupted dienes,
16.6%) contributing to about 65% of the total fatty acids, while alkenylacyl CPL was rich in the saturated acids 16∶0 (32.0%)
and 18∶0 (9.2%). In the alkylacyl EPL, 16∶0, 18∶1n−9, 18∶0 and 16∶1n−7 were prominentsn-2 fatty acids and accounted for 30.6%, 10.0%, 9.8%, and 8.3%, respectively. Polyunsaturated fatty acids were detected, but
were present at extremely low percentages. Majorsn-2 fatty acids in alkylacyl CPL were 16∶0 (25.4%), 22∶6n−3 (16.0%) and 20∶5n−3 (8.4%). The major fatty acids of diacyl EPL
were 20∶5n−3 (22.3%), 16∶0 (17.9%), and 18∶0 (16.1%), and those of diacyl CPL were 16∶0 (30.4%), 20∶5n−3 (17.6%) and 18∶1n−7
(7.4%). 相似文献
5.
Ethanolamine glycerophospholipids from the brains of both trout and cod comprised 36–38% of 1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine (GPE) determined using two methods. In 1-O-alk-1′-enyl-2-acyl-GPE from trout brain, the main molecular species were 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1, which totalled
63.3%, while polyunsaturated fatty acid (PUFA) containing species totalled only 18.2%. 1-O-Alk-1′-enyl-2-acyl-GPE from cod brain was much more unsaturated with PUFA containing species totalling 52.6%, of which 18∶0a/20∶5n−3,
18∶1a/20∶5n−3 and 18∶1a/22∶6n−3 were predominant. In cod 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1 were the only other species
present at over 5% each, totalling 31.8%. In both cod and trout, small amounts of species containing 22∶4n−6 were found. The
results of this and earlier studies indicate that there is considerable specificity of composition at the level of molecular
species between different lipid classes and subclasses.
Molecular species of 1-O-alk-1′-enyl-2-acyl-GPE are abbreviated as follows:e.g., 16∶0a/18∶1 GPE is 1-O-hexadec-1′-enyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. The corresponding diacyl species, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine, is abbreviated as 16∶0/18∶1. 相似文献
6.
The contents and compositions of the 1-O-alk-1′-enyl-2-acyl, 1-O-alkyl-2-acyl, and 1,2-diacyl glycerophospholipids in the muscle and viscera of the ascidianHalocynthia roretzi, and of the gonad of the sea urchinStrongylocentrotus intermedius, which are eaten to some extent in Alaska and in Asia, were analyzed by gas-liquid chromatography. 1-O-Alk-1′-enyl-2-acyl glycerophospholipids were found in all of the samples, accounting for 64.4–69.0% of the ethanolamine glycerophospholipid
(EPL). By contrast, the levels of the 1-O-Alk-1′-enyl-2-acyl choline glycerophospholipids (CPL) were low (3.1–5.7%). CPL was rich in the 1-O-alkyl-2-acyl subclass amounting to 12.5–23.9% in the ascidian sample. The level of CPL in the sea urchin gonad was extremely
high, amounting to 46.1%. The most prominent alkyl chains in thesn-1 position of CPL from the ascidian muscle were 16∶0 (44.6%), 18∶1 (26.5%), and 18∶0 (10.7%), and of CPL from the sea urchin
gonad were 18∶0 (36.2%), 16∶0 (33.0%), and 18∶1 (17.8%). Unusually high levels of odd-numbered alkyl chains, e.g., 19∶0 andanteiso 17∶0, were detected in the CPL of all samples. The prominent alkenyl chains of EPL were 18∶0 (69.4%), 16∶0 (10.0%), and 18∶1
(8.54%) (not counting the vinyl double bond) for the sea urchin gonad. Relatively high levels of 20∶1 alkenyl chains were
also present. The glycerolsn-2 positions contained high proportions of polyunsaturated fatty acids. Thus, 20∶5n-3 (43.6%) and 22∶6n-3 (20.1%) were most
abundant in the alkylacyl CPL from the ascidian muscle and 20∶5n-3 (54.9%) and 20∶4n-6 (30.1%) in alkylacyl CPL from the sea
urchin gonad. Despite a possible interconversion of the alkyl and alkenyl chains of each class of the ether phospholipids,
they showed few features in common. 相似文献
7.
A simple method for synthesizing diastereomerically pure phosphatidylglycerols (PtdGro), namely, 1,2-diacyl-sn-glycero-3-phospho-3′-sn-glycerol (R,R configuration) and 1,2-diacyl-sn-glycero-3-phospho-1′-sn-glycerol (R,S configuration) was established. For this purpose, diastereomeric 1,2-O-isopropylidene PtdGro were prepared from 1,2-diacyl-sn-glycero-3-phosphocholine (PtdCho) and enantiomeric 1,2-O-isopropylideneglycerols by transphosphatidylation with phospholipase D (PLD) from Actinomadura sp. This species was selected because of its higher transphosphatidylation activity and lower phosphatidic acid (PtdOH) formation
than PLD from some Streptomyces species tested. The reaction proceeded well, giving almost no hydrolysis of PtdCho to PtdOH in a biphasic system consisting
of diethyl ether and acetate buffer at 30°C. The isopropylidene protective group was removed by heating the diastereomeric
isopropylidene PtdGro at 100°C in trimethyl borate in the presence of boric acid to obtain the desired PtdGro diastereomers.
The purities of the products, which were determined by chiral-phase HPLC, were exclusively dependent on the optical purities
of the original isopropylideneglycerols used. The present method is simple and can be utilized for the synthesis of pure PtdGro
diastereomers having saturated and unsaturated acyl chains. 相似文献
8.
Racemic heavy isotope analogs of 1-O-alkyl-sn-glycero-3-phosphocholine (lysoPAF) and 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine (PAF) were prepared for use as internal standards to facilitate quantitative studies based on mass
spectrometry. Starting from pentadencane-1,15-diol andrac-glycerol-1,2-acetonide, a convergent synthesis of 1-O-[16′-2H3]hexadecyl and 1-O-[18′-2H3]octadecylrac-glycero-3-phosphocholine and their acetyl derivatives is described. Three deuterium atoms were introduced at the terminal
position of the 1-O-alkyl group by displacement of thep-toluensulfonyl group from 1-O-alkyl-15′-p-toluensulfonate and 1-O-alkyl-17′-p-toluensulfonate with [2H3]-methylmagnesium iodide. The 1-O-alkyl-17′-p-toluensulfonate was obtained by reaction of the 1-O-alkyl-15′-p-toluensulfonate with allylmagnesium bromide, followed by reductive ozonolysis and treatment withp-toluenesulfonyl chloride. The hydroxyl group at C-2 was protected by a benzyl group and removed at a late stage in the synthesis.
This provided the corresponding lysoderivatives or allowed preparation of racemic PAF by subsequent acetylation of the free
hydroxy group. The phosphocholine moiety was introduced at glycerol C-3 by reaction with bromoethyldichlorophosphate and trimethylamine.
The synthetic compounds were analyzed by FAB/MS and GC/NICIMS. They were shown to contain less than 0.6% protium impurity. 相似文献
9.
The differences in distribution of geometric isomers of unsaturated PC hydroperoxides generated by free radical oxidation
were compared, as corresponding hydroxy analogs, in heterogeneous liposomes and in a homogeneous methanol solution by using
HPLC with UV detection due to the presence of conjugated dienes. Identification of fractionated peak components was carried
out by GC-MS. When the oxidation of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine, PC(16∶0/18∶2), was initiated in liposomes by a hydrophilic azo radical initiator, and in a methanol
solution by a hydrophobic azo radical initiator, there was no significant difference in the relative percentages of 1-palmitoyl-2-(9-hydroxy-trans-10,trans-12-octadecadienoyl)-sn-glycero-3-phosphocholine (9-t,t-OH PC) and 1-palmitoyl-2-(13-hydroxy-trans-9,trans-11-octadecadienoyl)-sn-glycero-3-phosphocholine (13-t,t-OH PC) between the PC oxidized in liposomes and in the methanol solution. For the oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, PC(16∶0/20∶4), the relative percentage of 1-palmitoyl-2-(5-hydroxy-trans-6,cis-8,11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (5-OH PC) was significantly higher (P<0.01) than that of 1-palmitoyl-2-(15-hydroxy-cis-5,8,11,trans-13-eicosatetraenoyl)-sn-glycero-3-phosphocholine (15-OH PC) in liposomes. For the homogeneous methanol solution of PC(16∶0/20∶4), the relative percentage
of 5-OH PC was close to that of 15-OH PC. For the PC(16∶0/20∶4) oxidized in bulk with added pentamethylchromanol, the individual
amount of 15-OH PC, 1-palmitoyl-2-(11-hydroxy-cis-5,8trans-12,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (11-OH PC), 1-palmitoyl-2-(12-hydroxy-cis-5,8,trans-10,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (12-OH PC), 1-palmitoyl-2-(8-hydroxy-cis-5,trans-9,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (8-OH PC), 1-palmitoyl-2-(9-hydroxy-cis-5,trans-7,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (9-OH PC), and 5-OH PC were close to each other compared to the corresponding values in liposomes
and in methanol solution. The results obtained by gel permeation chromatography of the PC liposomes containing hydrophilic
2,2′-azobis-2-amidinopropane) dihydrochloride (AAPH) suggest that the AAPH added to the liposomes of PC(16∶0/20∶4) was partitioned
into the water phase and out of the hydrophobic region of the fatty acyl moieties of the PC. These results confirm that the
distance that exists in the bis-allylic carbons of the unsaturated fatty acyl moieties of PC from the interface between the
hydrophilic region of PC and the water phases played an important role in influencing hydrogen abstraction to form a symmetrical
distribution of hydroperoxide isomers in both the heterogeneous liposomes and the homogeneous methanol solution. 相似文献
10.
Junko Sugatani Kazuyo Fujimura Masao Miwa Kiyoshi Satouchi Kunihiko Saito 《Lipids》1991,26(12):1347-1353
The molecular heterogeneity of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (alkylacetyl-GPC) and 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (acylacetyl-GPC) in normal rat glandular stomach was studied by gas chromatography/mass spectrometry
(GC/MS) and tandem mass spectrometry. The percentage compositions of the molecular species of 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC
in the antrum were, respectively. 1-alkyl [16∶0 (34%) and 18∶0 (66%)]-2-acetyl-GPC and 1-acyl [16∶0 (60%), 18∶0 (14%) and
18∶1 (26%)]-2-acetyl-GPC. The alkyl chain composition of 1-alkyl-2-acyl-GPC was quite different from that of 1-alkyl-2-acyl-GPC
in both the antrum and corpus, demonstrating a high degree of selectivity of alkyl chain utilization in PAF biosynthesis.
The amount of 1-acyl-2-acetyl-GPC was much greater than that of 1-alkyl-2-acetyl-GPC. The molecular heterogeneity of 1-alkyl-2-acetyl-GPC
and 1-acyl-2-acetyl-GPC in the corpus was similar to that in the antrum. Water-immersion stress affected not only the amount
of 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC, but also their molecular heterogeneity in the antrum and corpus. Whereas
the amounts of 1-hexadecyl-2-acetyl-GPC and 1-acyl [16∶0, 18∶0 and 18∶1]-2-acetyl-GPC decreased markedly (to less than one-fifth)
in the antrum after such stress for 1 hr, the amount of 1-octadecyl-2-acetyl-GPC increased markedly (up to 4-fold) in the
corpus and severe lesions were observed after stress for 7 hr. The changes may be associated with the pathogenicity of gastric
ulcers.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
11.
The molecular species composition of the major glycerophospholipids from white matter of human brain were determined by high-performance
liquid chromatography of the 3,5-dinitrobenzoyl derivatives of the corresponding diradylglycerols. In phosphatidylcholine
(PC) and phosphatidylserine (PS), molecular species containing only saturated fatty acids (SFA) and monounsaturated fatty
acids (MUFA) comprised 85.7 and 82.4% of the respective totals, with 18∶0/18∶1 predominant in PS and 16∶0/18∶1 in PC. These
molecular species were also abundant in phosphatidylethanolamine (PE), but in this phospholipid species containing polyunsaturated
fatty acids (PUFA), largely 18∶0/22∶6n−3 and 18∶0/20∶4n−6, accounted for over half the total; 18∶1/18∶1 was also abundant
in PE. In contrast, 1-O-alk-1′-enyl-2-acylsn-glycero-3-phosphoethanolamine (GPE) had much more SFA- and MUFA-containing species, predominantly 16∶0a/18∶1, 18∶0a/18∶1
and 18∶1a/18∶1, with low amounts of species containing 20∶4n−6 and 22∶6n−3. In alkenylacyl GPE, 22∶4n−6 was the major PUFA
and 16∶0a/22∶4n−6 and 18∶1a/22∶4n−6 the main PUFA-containing species. There was six times more 22∶6n−3, twice as much 20∶4n−6
and half the amount of 22∶4n−6 in PE as compared to alkenylacyl GPE.
Molecular species are abbreviated as follows:e.g., 16∶0/18∶1 PE is 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine; the corresponding alkenylacyl species, 1-O-hexadec-1′-enyl-2-oleoyl-sn-glycero-3-phosphoethanolamine is 16∶0a/18∶1. 相似文献
12.
Previous studies in our laboratory have shown that marine oils, with high levels of eicosapentaenoic (EPA, 20∶5n−3) and docosahexaenoic
acids (DHA, 22∶6n−3), inhibit the growth of CT-26, a murine colon carcinoma cell line, when implanted into the colons of male
BALB/c mice. Anin vitro model was developed to study the incorporation of polyunsaturated fatty acids (PUFA) into CT-26 cells in culture. PUFA-induced
changes in the phospholipid fatty acid composition and the affinity with which different fatty acids enter the various phospholipid
species and subspecies were examined. We found that supplementation of cultured CT-26 cells with either 50 μM linoleic acid
(LIN, 18∶2n−6), arachidonic acid (AA, 20∶4n−6), EPA, or DHA significantly alters the fatty acid composition of CT-26 cells.
Incorporation of these fatty acids resulted in decreased levels of monounsaturated fatty acids, while EPA and DHA also resulted
in lower levels of AA. While significant elongation of both AA and EPA occurred, LIN remained relatively unmodified. Incorporation
of radiolabeled fatty acids into different phospholipid species varied significantly. LIN was incorporated predominantly into
phosphatidylcholine and had a much lower affinity for the ethanolamine phospholipids. DHA had a higher affinity for plasmenylethanolamine
(1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphoethanolamine) than the other fatty acids, while EPA had the highest affinity for phosphatidylethanol-amine
(1,2-diacyl-sn-glycero-3-phosphoethanolamine). These results demonstrate that,in vitro, significant differences are seen between the various PUFA in CT-26 cells with respect to metabolism and distribution, and
these may help to explain differences observed with respect to their effects on tumor growth and metastasis in the transplantable
model. 相似文献
13.
Using chiral-phase HPLC, we determined the stereochemical configuration of the phosphatidylglycerols (PtdGro) synthesized
in vitro from 1,2-diacyl-sn-glycero-3-phosphocholine (PtdCho, R configuration) or 1,2-diacyl-sn-glycero-3-phosphoethanolamine (PtdEtn, R configuration) and glycerol by transphosphatidylation with bacterial phospholipase D (PLD). The results obtained with PLD
preparations from three Streptomyces strains (S. septatus TH-2, S. halstedii K5, and S. halstedii subsp. scabies K6) and one Actinomadura species were compared with those obtained using cabbage and peanut PLD. The reaction was carried out at 30°C in a biphasic
system consisting of diethyl ether and acetate buffer. The resulting PtdGro were then converted into bis(3,5-dinitrophenylurethane)
derivatives, which were separated on an (R)-1-(1-naphthyl)ethylamine polymer. In contrast to the cabbage and peanut PLD, which gave equimolar mixtures of the R,S and R,R diastereomers, as previously established, the bacterial PLD yielded diastereomixtures of 30–40% 1,2-diacyl-sn-glycero-3-phospho-1′-sn-glycerol (R,S configuration) and 60–70% 1,2-diacyl-sn-glycero-3-phospho-3′-sn-glycerol (R,R configuration). The highest disproportionation was found for the Streptomyces K6 species. The present study demonstrates that bacterial PLD-catalyzed transphosphatidylation proceeds to a considerable
extent stereoselectively to produce PtdGro from PtdCho or PtdEtn and prochiral glycerol, indicating a preference for the sn-3′
position of the glycerol molecule. 相似文献
14.
In mammalian systems, platelet-activating factor, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, (PAF) is rapidly inactivated by a deacetylation/reacylation system that produces 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine which is highly enriched in arachidonic acid. There is some evidence that n−3 fatty acids may have
an impact on this system in humans but the nature of this impact is unclear. In rainbow trout, n−3 fatty acids are known to
be essential dietary components which are derived through the food chain. Substantial quantities of n−3 fatty acids are found
in trout membrane phospholipids. We show here that in sharp contrast to mammalian cells, trout cells acylate lyso platelet-activating
factor, alkyl-GPC, 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine, (lyso-PAF) with a high degree of specificity for n−3 fatty acids. When [3H]lysoPAF was incubated with these cells, only three molecular species of alkylacylglycerophosphocholine were produced, and
92% contained n−3 fatty acids. Since isolated membranes yielded similar results, it appears that the acylation proceedsvia a coenzyme A-independent transacylase as found in mammalian systems. 相似文献
15.
M. P. Murari R. Murari S. Parthasarathy C. A. Guy V. V. Kumar B. Malewicz Wolfgang J. Baumann 《Lipids》1990,25(10):606-612
Described is a reaction sequence for the total synthesis of lyso platelet activating factor (lysoPAF; 1-O-alkyl-sn-glycero-3-phosphocholine) and its enantiomer. The procedure is versatile and yields optically pure isomers of defined chain
length. The synthesis is equally suited for the preparation of lysoPAF analogues and its enantiomers with unsaturation in
the long aliphatic chain. First,rac-1(3)-O-alkylglycerol is prepared by alkylation ofrac-isopropylideneglycerol with alkyl methanesulfonate followed by acid-catalyzed removal of the ketal group. The primary hydroxy
group of alkylglycerol is then protected by tritylation, the secondary hydroxy group is acylated, and the protective trityl
group is removed under mild acidic conditions with boric acid on silicic acid, essentially without acyl migration. Condensation
of the diradylglycerol with bromoethyl dichlorophosphate in diethyl ether, hydrolysis of the resulting chloride, and nucleophilic
displacement of the bromine with trimethylamine givesrac-1-O-alkyl-2-acylglycero-3-phosphocholine in good overall yield. The racemic alkylacylglycerophosphocholine is finally treated
with snake venom phospholipase A2 (Ophiophagus hannah) which affords 1-O-alkyl-sn-glycero-3-phosphocholine (lysoPAF) of natural configuration in optically pure form. The “unnatural” 3-O-alkyl-2-O-acyl-sn-glycerol-1-phosphocholine enantiomer, which is not susceptible to phospholipase A2 cleavage, gives 3-O-alkyl-sn-glycero-1-phosphocholine upon deacylation with methanolic sodium hydroxide. Homogeneity and structure of the intermediates
and final products were ascertained by carbon-13 nuclear magnetic resonance spectroscopy on monomeric solutions. 相似文献
16.
The molecular species compositions of the main diacyl phosphoglyceride classes and ether-linked subclasses from sperm of three
species of fish, sea bass Dicentrarchus labrax, Atlantic salmon Salmo salar and Chinook salmon Onchorhynchus tsawytscha, were determined. The phospholipids from sperm were highly unsaturated, dipolyunsaturated fatty acid (diPUFA) molecular species
comprised 64.6 to 71.8% of phosphatidylserine (PS), 10.1 to 17.4% of phosphatidylethanolamine (PE), and 3.3 to 10.1% of phosphatidylcholine
(PC). In sea bass sperm, di22∶6n-3 phospholipid was the predominant diPUFA molecular species, but in both salmon species 22∶5n-3/22∶6n-3
was also a major constituent of PS. Phospholipids containing 22∶6n-3 dominated in sea bass sperm with 16∶0/22∶6n-3 as a major
component of PC and PE, and 18∶0/22∶6n-3 of PE and PS in addition to di22∶6n-3 in the latter two classes. In contrast, both
salmon species contained much more 20∶5n-3 and less 22∶6n-3 so that saturated/20∶5n-3 and monounsaturated/20∶5n-3 molecular
species were more abundant than the corresponding molecules containing 22∶6n-3. Ether-linked lipids comprised 11.3–36.3% of
choline and ethanolamine phosphoglycerides in each fish species. Molecular species containing 22∶6n-3 were the major components
of 1-O-alkyl-2-acyl-glycerophosphocholine, especially 16∶0a/22∶6n-3 in sea bass and 18∶1a/∶6n-3 in the two salmon species, while
in 1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine, 16∶0a/22∶6n-3 was the major component in both salmon and 18∶0a/22∶6n-3 in
sea bass with 18∶1a/22∶6n-3 abundant in all three species. In Atlantic salmon 1-O-alkyl-2-acylglycerophosphoethanolamine comprised 24.6% of ethanolamine glycerophospholipids which were predominantly 16∶0a/22∶6n-3
and 18∶1a/22∶6n-3. Phosphatidylinositol from sperm was dominated by stearoyl/C20 PUFA molecular species, in sea bass overwhelmingly 18∶0/20∶4n-6, while in both salmon species 18∶0/20∶4n-6 and 18∶0/20∶5n-3
were equally abundant. 相似文献
17.
1-Acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-2-acetyl GPC) was found in the fraction of platelet-activating factor obtained from stimulated
human polymorphonuclear leukocytes (PMN). The amount of 1-acyl-2-acetyl GPC obtained from 1×107 PMN stimulated with ionophore A23187 at 37 C for 15 min ranged from 8 to 56 pmol (32±10 pmol, mean±standard error; n=4).
The main species was 16∶0 palmitoyl (17±5 pmol), followed by 18∶0 stearoyl (8±3 pmol) and 18∶1 oleoyl (7±3 pmol).
Although the physiological significance is unknown, 1-acyl-2-acetyl GPC was always detected when 1-alkyl-2-acetyl GPC was
detected. 相似文献
18.
We studied changes in lipid composition of human promyelocytic leukemia cells (HL-60) on differentiation to the macrophage/monocytic
lineage by treatment with the phorbol ester, 12-O-tetradecanoyl-phorbol-13-acetate. Differentiation was accompanied by: (i)
a decrease in the level of phospholipids; (ii) a greater amount of triacylglycerols; (iii) an increase in 1-alk-1′-enyl-2-acyl-
and 1-alkyl-2-acyl-sn-glycero-3-phosphoethanolamine and a decrease in 1-alkyl-2-acyl-sn-glycero-3-phosphocholine; and (iv) an increase in the level of arachidonic acid in ethanolamine phospholipids. The increased
levels of ether-linked lipids and of arachidonic acid in ethanolamine phospholipids are consistent with an enhanced biosynthesis
of platelet-activating factor and eicosanoids, which are particularly important in the macrophage function. 相似文献
19.
Phospholipid molecular species from human placenta lipids 总被引:1,自引:0,他引:1
The phospholipid molecular species from a large-scale preparation of human placenta lipids were analyzed. The major placental
phospholipids were choline glycerophospholipids (CPL) (53.2 wt%), sphingomyelin (21.7 wt%) and ethanolamine glycerophospholipids
(EPL) (14.6 wt%). 1,2-Diacyl-glycerophosphocholine was the most abundant subclass of CPL (91.7 mol%), while EPL contained
1,2-diacyl (54.6 mol%) and 1-alk-1′-enyl-2-acyl (43.8 mol%) subclasses. The level of polyunsaturated fatty acids (PUFA) in
total phospholipids was remarkably constant (38.4–39.9 mol%) within all placental batches tested. The long-chain PUFA, mainly
20∶4n−6 and 22∶6n−3 of the n−6 and n−3 series, respectively, were found in high proportion in all phospholipid classes, especially
in EPL (46.7 mol%) and in inositol glycerophospholipids (IPL) (39.9 mol%). CPL and serine glycerophospholipids were much richer
in 18∶1n−9 and 18∶2n−6. High levels of molecular species with arachidonic acid in thesn-2 position were found particularly in 1-alk-1′-enyl-2-acyl-glycerophospho-ethanolamine (with 24.0 mol% 16∶0 and 22.0 mol%
18∶0 insn-1 position) and in 1,2-diacyl glycerophosphoinositol with 42.6 mol% 18∶0 insn-1 position. EPL subclasses were rich in 22∶6n−3, which occurs mainly as 16∶0/22∶6n−3 (11.7 mol%) in the polasmalogen form
and as 18∶0/22∶6n−3, 16∶0/22∶6n−3 and 18∶1/22∶6n−3 in the diacyl forms. Based on their availability and composition, placental
phospholipids could be of interest, for example, for supplementing artificial milk preparations with n−3 and n−6 long-chain
PUFA for newborn infants with insufficiently developed 18∶2n−6 and 18∶3n−3 desaturation/elongation. 相似文献
20.
The synthesis of 1,2 dilinoleoylsn-3-glycerophosphorylcholine (1,2-18∶2-sn-3-GPC) and 1,2 dipalmitoylsn-3-glycerophosphorylcholine (1,2-16∶0-sn-3-SPC) is described. Synthesis was accomplished by acylating free glycerophosphorylcholine (GPC) with the anhydride and potassium
salt of the desired acid. Purification of 1,2-16∶0-sn-3-GPC was accomplished by crystallization, while purification of 1,2-18∶2-sn-3-GPC required the use of alumina column chromatography and then crystallization from acetone at −7C.
Scientific contribution N. 491, Agricultural Experiment Station, University of Connecticut, Storrs. 相似文献