LIPID SYNTHESIS IN RAT LIVER PARTICLES: DIVERSION OF SYNTHESIS FROM TRIGLYCERIDE TO LECITHIN BY THE IN VITRO ADDITION OF CYTIDINE DIPHOSPHATE CHOLINE

1962 ◽  
Vol 40 (1) ◽  
pp. 1051-1058 ◽  
Author(s):  
K. P. Strickland ◽  
R. J. Rossiter
Keyword(s):  
Fatty Acid ◽  
Phosphatidic Acid ◽  
Experimental Test ◽  
Lipid Synthesis ◽  
Phosphatidyl Inositol ◽  
Fatty Acyl ◽  
Phosphatidic Acids ◽  
Acyl Coenzyme A ◽  
Cytidine Diphosphate

When particle preparations from rat or chicken liver were incubated in a suitable medium containing α-glycerophosphate-C14, radioactivity was recovered from lecithin, phosphatidyl inositol, phosphatidic acid, and triglyceride. Whole homogenate and various particle preparations catalyzed the dephosphorylation of a number of phosphatidic acids, with the liberation of inorganic P.It is currently believed that liver preparations are capable of catalyzing the esterification of L-α-glycerophosphate, with the formation of L-α-phosphatidic acid, which subsequently may be dephosphorylated to form D-α,β-diglyceride. The diglyceride so formed may then give rise either to lecithin, by combining with phosphorylcholine from cytidine diphosphate choline, or to triglyceride, by combining with fatty acid from fatty acyl coenzyme A. If these reactions occur in liver particle preparations, it should be possible, by the addition in vitro of unlabelled cytidine diphosphate choline, to divert the synthesis of lipid from the formation of triglyceride to the formation of lecithin. In experiments designed to put this hypothesis to the experimental test, such a diversion of lipid synthesis was achieved.

LIPID SYNTHESIS IN RAT LIVER PARTICLES: DIVERSION OF SYNTHESIS FROM TRIGLYCERIDE TO LECITHIN BY THE IN VITRO ADDITION OF CYTIDINE DIPHOSPHATE CHOLINE

1962 ◽  
Vol 40 (8) ◽  
pp. 1051-1058 ◽  
Author(s):  
K. P. Strickland ◽  
R. J. Rossiter
Keyword(s):  
Fatty Acid ◽  
Phosphatidic Acid ◽  
Experimental Test ◽  
Lipid Synthesis ◽  
Phosphatidyl Inositol ◽  
Fatty Acyl ◽  
Phosphatidic Acids ◽  
Acyl Coenzyme A ◽  
Cytidine Diphosphate

When particle preparations from rat or chicken liver were incubated in a suitable medium containing α-glycerophosphate-C14, radioactivity was recovered from lecithin, phosphatidyl inositol, phosphatidic acid, and triglyceride. Whole homogenate and various particle preparations catalyzed the dephosphorylation of a number of phosphatidic acids, with the liberation of inorganic P.It is currently believed that liver preparations are capable of catalyzing the esterification of L-α-glycerophosphate, with the formation of L-α-phosphatidic acid, which subsequently may be dephosphorylated to form D-α,β-diglyceride. The diglyceride so formed may then give rise either to lecithin, by combining with phosphorylcholine from cytidine diphosphate choline, or to triglyceride, by combining with fatty acid from fatty acyl coenzyme A. If these reactions occur in liver particle preparations, it should be possible, by the addition in vitro of unlabelled cytidine diphosphate choline, to divert the synthesis of lipid from the formation of triglyceride to the formation of lecithin. In experiments designed to put this hypothesis to the experimental test, such a diversion of lipid synthesis was achieved.

Synthesis of molecular classes of cytidine diphosphate diglyceride by rat liver in vivo and in vitro

1977 ◽  
Vol 55 (11) ◽  
pp. 1153-1158 ◽  
Author(s):  
W. Thompson ◽  
G. MacDonald
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
Rat Liver ◽  
Liver Microsomes ◽  
Phosphatidyl Inositol ◽  
Convincing Evidence ◽  
Rat Liver Microsomes ◽  
Cytidine Diphosphate

Cytidine diphosphate (CDP) diglyceride isolated from pooled rat liver was shown like phosphatidyl inositol to contain stearate and arachidonate as the major fatty acids. On the other hand palmitate and oleate were the predominant fatty acids of total liver phosphatidic acid.Labelling of molecular classes of phosphatidic acid, CDP-diglyceride, and phosphatidyl inositol was examined in liver at various time intervals after either intraportal or intrajugular injections of [3H]glycerol. In general the major flux of radioactivity was through the oligoenoic classes [Δ1 and Δ2] of phosphatidic acid. In contrast the labelling of oligoenoic classes of CDP-diglyceride was less and of polyenoic classes [Formula: see text] significantly enhanced, raising the possibility that there may be some discrimination in selection of species of phosphatidic acid for liponucleotide synthesis. After intrajugular injections of isotope the monoenoic classes of phosphatidyl inositol were most highly labelled but between 5 and 240 min there was a progressive decrease of radioactivity in this class and increase in the tetraenoic species, presumably as a result of deacylation and reacylation reactions. The backflow of radioactivity from phosphatidyl inositol was deemed not a likely explanation for the observed labelling pattern of CDP-diglyceride.The conversion of sonicated dispersions of [3H]phosphatidic acid, labelled in the glycerol moiety, to CDP-diglyceride by rat liver microsomes was examined. There was slightly less label in the oligoenoic classes and slightly more in trienoic and polyenoic (> Δ4) classes of CDP-diglyceride as compared with phosphatidic acid. These differences were much smaller in vitro than those observed in vivo. The in vitro data provide no convincing evidence for a high enough selectivity to explain the differences in arachidonate content between phosphatidic acid and the liponucleotide.

Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver

1984 ◽  
Vol 247 (3) ◽  
pp. G305-G310
Author(s):  
W. J. Kortz ◽  
J. R. Nashold ◽  
M. R. Greenfield ◽  
H. Hilderman ◽  
S. H. Quarfordt
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Fatty Acyl ◽  
Liver Fat ◽  
Molar Ratio ◽  
Perfusion System ◽  
In Vitro Perfusion ◽  
Arterial Inflow ◽  
High Concentrations

The metabolism of double-labeled triglyceride in a synthetic emulsion was defined in an in vitro perfusion system of rat hind end and liver described previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8): G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined in the absence of added apoproteins and with additions of human CII and both CII and CIII. Without apoprotein, a pronounced lipolysis of the triglyceride was recognized by high concentrations of radiolabeled glycerol and free fatty acid in the perfusate. The removal of an aliquot of hind-end venous effluent 5 min after adding the labeled triglyceride emulsion to the arterial inflow demonstrated a brisk lipolysis of the substrate when incubated outside the perfusion system. The addition of CII protein to the emulsion before its introduction into the tandem system eliminated perfusate lipolysis, both within the perfusion system and in incubations of aliquots withdrawn from the system. Intravascular lipolysis was not seen with triglyceride emulsions containing both CII and CIH or when an aliquot of hind-end venous effluent was incubated with triglycerides that had not been exposed to the perfusion system. The intravascular lipolysis observed for the [14C]triglyceride added to the tandem system without apoproteins was associated with relatively greater recoveries of 14C-fatty acyl in liver, fat, and muscle and relatively greater recoveries of 14CO2 than when CII alone or both CII and CIII were added with the triglyceride. The addition of CIII to CII in a 1:1 molar ratio increased the recovery of 14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The regulation of triglyceride synthesis and fatty acid synthesis in rat epididymal adipose tissue. Effects of insulin, adrenaline and some metabolites in vitro

1970 ◽  
Vol 119 (2) ◽  
pp. 193-219 ◽  
Author(s):  
E. D. Saggerson ◽  
A. L. Greenbaum
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Fatty Acyl ◽  
Mass Action ◽  
Hexose Monophosphate ◽  
Tissue Concentrations ◽  
Hexose Monophosphate Pathway ◽  
Long Chain

1. Adipose tissues from rats fed a balanced diet were incubated in the presence of glucose (20mm) with the following additions: insulin, anti-insulin serum, insulin+acetate, insulin+pyruvate, insulin+lactate, insulin+phenazine methosulphate, insulin+oleate+albumin, insulin+adrenaline+albumin, insulin+6-N-2′-O-dibutyryl 3′:5′-cyclic AMP+albumin. 2. Measurements were made of the whole tissue concentrations of adenine nucleotides, hexose phosphates, triose phosphates, glycerol 1-phosphate, 3 phosphoglycerate, 6-phosphogluconate, long-chain fatty acyl-CoA, acid-soluble CoA, citrate, isocitrate, malate and 2-oxoglutarate, and of the release into the incubation medium of lactate, pyruvate and glycerol after 1h of incubation. 3. Fluxes of [14C]glucose carbon through the major pathways of glucose metabolism were calculated from the yields of 14C in various products after 2h of incubation. Fluxes of [14C]acetate, [14C]pyruvate or [14C]lactate carbon in the presence of glucose were also determined. 4. Measurements were also made of the whole-tissue concentrations of metabolites in tissues taken directly from Nembutal-anaesthetized rats. 5. Whole tissue mass-action ratios for phosphofructokinase, phosphoglucose isomerase and the combined (aldolase×triose phosphate isomerase) reaction were similar in vivo and in vitro. The reactants of phosphofructokinase appeared to be far from mass-action equilibrium. In vitro, the reactants of hexokinase also appeared to be far from mass-action equilibrium. 6. Correlation of observed changes in glycolytic flux with changes in fructose 6-phosphate concentration suggested that phosphofructokinase may show regulatory behaviour. The enzyme appeared to be activated in the presence of oleate or adrenaline and to be inhibited in the presence of lactate or pyruvate. 7. Evidence is presented that the reactants of lactate dehydrogenase and glycerol 1-phosphate dehydrogenase may be near to mass-action equilibrium in the cytoplasm. 8. No satisfactory correlations could be drawn between the whole-tissue concentrations of long-chain fatty acyl-CoA, citrate and glycerol 1-phosphate and the observed rates of triglyceride and fatty acid synthesis. Under the conditions employed, the concentration of glycerol 1-phosphate appeared to depend mainly on the cytoplasmic [NAD+]/[NADH] ratios. 9. Calculated hexose monophosphate pathway flux rates roughly correlated with fatty acid synthesis rates and with whole tissue [6-phosphogluconate]/[glucose 6-phosphate] ratios. The relative rates of production of NADPH for fatty acid synthesis by the hexose monophosphate pathway and by the `malic enzyme' are discussed. It is suggested that all NADH produced in the cytoplasm may be used in that compartment for reductive synthesis of fatty acids, lactate or glycerol 1-phosphate.

scholarly journals Biochemical characteristics of AtFAR2, a fatty acid reductase from Arabidopsis thaliana that reduces fatty acyl-CoA and -ACP substrates into fatty alcohols

2016 ◽  
Vol 63 (3) ◽  
Author(s):  
Thuy T. P. Doan ◽  
Anders S. Carlsson ◽  
Sten Stymne ◽  
Per Hofvander
Keyword(s):  
Arabidopsis Thaliana ◽  
Fatty Acid ◽  
Fatty Acyl ◽  
Fatty Alcohols ◽  
Abnormal Development ◽  
In Planta ◽  
Alcohol Production ◽  
Genes Encoding ◽  
In Vitro Data

Fatty alcohols and derivatives are important for proper deposition of a functional pollen wall. Mutations in specific genes encoding fatty acid reductases (FAR) responsible for fatty alcohol production cause abnormal development of pollen. A disrupted AtFAR2 (MS2) gene in Arabidopsis thaliana results in pollen developing an abnormal exine layer and a reduced fertility phenotype. AtFAR2 has been shown to be targeted to chloroplasts and in a purified form to be specific for acyl-ACP substrates. Here, we present data on the in vitro and in planta characterizations of AtFAR2 from A. thaliana and show that this enzyme has the ability to use both, C16:0-ACP and C16:0-CoA, as substrates to produce C16:0-alcohol. Our results further show that AtFAR2 is highly similar in properties and substrate specificity to AtFAR6 for which in vitro data has been published, and which is also a chloroplast localized enzyme. This suggests that although AtFAR2 is the major enzyme responsible for exine layer functionality, AtFAR6 might provide functional redundancy to AtFAR2.

scholarly journals The enzymology of short-chain fatty acyl-coenzyme A synthetase from seeds of Pinus radiata. Kinetic studies and a proposed reaction mechanism

1974 ◽  
Vol 137 (3) ◽  
pp. 435-442 ◽  
Author(s):  
Owen A. Young ◽  
John W. Anderson
Keyword(s):  
Fatty Acid ◽  
Pinus Radiata ◽  
Kinetic Studies ◽  
Single Species ◽  
Competitive Inhibitor ◽  
Fatty Acyl ◽  
Short Chain ◽  
Low Concentrations ◽  
High Concentrations ◽  
Acyl Coenzyme A

1. Short-chain fatty acyl-CoA synthetase from seeds of Pinus radiata was examined by acetate- and propionate-dependent PPi–ATP exchange. Reaction mixtures came to equilibrium almost instantly as judged by rates of exchange and analysis of an incubation mixture. 2. The activity of the enzyme was correlated with the concentration of MgP2O72- but not with the concentration of Mg2+, as judged by PPi–ATP exchange and fatty acyl AMP-dependent synthesis of ATP in the presence of PPi. In PPi–ATP exchange assays, no clear relationship between activity and any single species of ATP was apparent. 3. High concentrations of fatty acid inhibited PPi–ATP exchange. PPi–dATP exchange was less than PPi–ATP exchange at low concentrations of fatty acid, but at higher concentrations PPi–dATP exchange exceeded PPi–ATP exchange. The rate of synthesis of fatty acyl-CoA in the presence of dATP was less than with ATP. 4. ATP and propionate inhibited the synthesis of ATP from propionyl-AMP and PPi. The inhibition by ATP was competitive with respect to propionyl-AMP and non-competitive with respect to PPi. The inhibition by propionate was non-competitive with respect to propionyl-AMP and PPi. 5. AMP was a competitive inhibitor of propionyl-AMP-dependent synthesis of ATP and competitively inhibited propionate-dependent PPi–ATP exchange when ATP was the variable substrate. 6. It was concluded that the first partial reaction catalysed by the enzyme is ordered; ATP is the first substrate to react with the enzyme and PPi is probably the only product released.

scholarly journals Amelioration of Cryptosporidium parvum Infection In Vitro and In Vivo by Targeting Parasite Fatty Acyl-Coenzyme A Synthetases

2013 ◽  
Vol 209 (8) ◽  
pp. 1279-1287 ◽  
Author(s):  
F. Guo ◽  
H. Zhang ◽  
J. M. Fritzler ◽  
S. D. Rider ◽  
L. Xiang ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Coenzyme A ◽  
Fatty Acyl ◽  
Acyl Coenzyme A

FATTY ACID ETHYL ESTER FORMATION BY PLASMA IN VITRO

1966 ◽  
Vol 44 (2) ◽  
pp. 219-227 ◽  
Author(s):  
W. H. Newsome ◽  
J. B. M. Rattray
Keyword(s):  
Fatty Acid ◽  
Acid Ethyl Ester ◽  
Fatty Acyl ◽  
Ethyl Esters ◽  
Acyl Donor ◽  
Significant Activity ◽  
Fatty Acid Substrate ◽  
Ester Formation

The capacity of rat plasma to form ethyl esters when incubated with ethanol and fatty acid was examined. The process was found to be enzymatic and to involve primarily a direct esterification of fatty acid as opposed to a transesterification requiring a fatty acyl donor. Maximal esterification of oleic acid occurred at pH 6.0 but significant activity existed at physiological pH to indicate a capacity of the plasma to utilize ethanol and fatty acid in concentrations that might be expected in vivo. Both normal and post-heparin plasma were found to esterify endogenous free fatty acid. A major factor affecting the esterification process was the availability of fatty acid substrate and the governing role of plasma albumin in this respect is discussed.

scholarly journals Reconstruction of phospholipid synthesis by combing in vitro fatty acid synthesis and cell-free gene expression

2021 ◽  
Author(s):  
Sumie Eto ◽  
Rumie Matsumura ◽  
Mai Fujimi ◽  
Yasuhiro Shimane ◽  
Samuel Berhanu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Phospholipid Synthesis ◽  
Giant Vesicles ◽  
Phosphatidic Acids ◽  
A Cell ◽  
Free Gene

Phospholipid synthesis is a fundamental process that promotes cell propagation and, presently, is the most challenging issue in artificial cell research aimed at reconstituting living cells from biomolecules. Here, we constructed a cell-free phospholipid synthesis system that combines in vitro fatty acid synthesis and a cell-free gene expression system that synthesizes acyltransferases for phospholipid synthesis. Fatty acids were synthesized from acetyl-CoA and malonyl-CoA, then continuously converted into phosphatidic acids by the cell-free synthesized acyltransferases. Because the system can avoid the accumulation of synthetic intermediates that suppress the reaction, the yield of phospholipid has significantly improved from previous schemes (up to 400 μM). Additionally, by adding enzymes for recycling CoA, we synthesized phosphatidic acids from acetic acid and bicarbonate as carbon sources. The constructed system is available to express the genes from pathogenic bacteria and to analyze the synthesized phospholipids. By encapsulating our system inside giant vesicles, it would be possible to construct the artificial cells in which the membrane grows and divides sustainably.

Studies on the formation by rat brain preparations of CDP-diglyceride from CTP and phosphatidic acids of varying fatty acid compositions

1976 ◽  
Vol 54 (3) ◽  
pp. 249-260 ◽  
Author(s):  
H. H. Bishop ◽  
K. P. Strickland
Keyword(s):  
Fatty Acid ◽  
Phosphatidic Acid ◽  
Rat Brain ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Distribution ◽  
Assay Method ◽  
Detergent Solution ◽  
Significant Activity ◽  
Ph Optimum ◽  
Phosphatidic Acids

The enzyme, CTP:phosphatidate cytidylyltransferase (EC 2.7.7.41) which catalyses formation of CDP-diglyceride from CTP and phosphatidic acid has been studied in rat brain preparations and other tissues. Improvement, as judged by the higher tissue activities obtained, in the assay method for this enzyme was achieved through use of phosphatidic acids sonicated in buffer–detergent solution saturated with ether and containing bovine serum albumin and use of short incubation times which essentially provided a measure of initial rates. The enzyme of rat brain microsomes yielded with 1,2-dioleoylphosphatidic acid as substrate a pH optimum of 6.8 with maleate buffer and optimal concentrations of 60 mM for Mg2+, 6 mM for CTP and 250 μg per 0.8 ml for phosphatidic acid. Enzyme activity was mainly located in the 90 000 × g fraction (microsomal) with small but significant activity in the 12 000 × g fraction. Comparison of activities (nanomoles CTP incorporated per milligram protein per minute) amongst tissues showed the following order: brain, 1.87; liver, 1.32; lung, 1.19; small intestine, 1.00; kidney, 0.69; heart, 0.41; diaphragm, 0.07; skeletal muscle, 0.02. Examination of the effect of varying the fatty acid composition in the phosphatidic acids added exogenously gave the following order (activities in parentheses): 1-stearoyl-2-oleoyl- (5.58), 1-oleoyl-2-stearoyl- (5.37), 1,2-dioleoyl- (4.49) 1-palmitoyl-2-oleoyl- (3.85), 1-stearoyl-2-arachidonoyl- (3.31), 1-arachidonoyl-2-stearoyl- (3.16), 1,2-diarachidonoyl- (0.72), 1,2-dicaproyl- (0.67), 1,2-dipalmitoyl- (0.67) and 1,2-distearoyl-(0.18). The single bis- and lysophosphatidic acids tested were inactive as substrates. Apart from a possible preference for one or more unsaturated fatty acids the transferase enzyme showed no selectivity in respect to the fatty acid distribution of phosphatidic acids.

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