scholarly journals The synthesis of fatty acids in avocado mesocarp and cauliflower bud tissue

1975 ◽  
Vol 146 (2) ◽  
pp. 425-437 ◽  
Author(s):  
P J Weaire ◽  
R G Kekwick
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Gradient Centrifugation ◽  
Fatty Acid Synthetase ◽  
Synthetase Activity ◽  
Acid Biosynthesis ◽  
Avocado Fruit ◽  
Malonyl Coa ◽  
Fatty Acid Synthetase Activity

1. Plastid and mitochondrial preparations were obtained by density-gradient centrifugation of homogenates made by gentle disintergration of avocado fruit mesocarp and cauliflower bud tissue. 2. The mitochondrial preparations had respiratory activity but did not incorporate [1-14C]acetate into fatty acids. 3. The plastid preparations incorporated [1-14C]acetate into the range of fatty acids found in the parent tissue. No fatty acid synthetase activity could be detected in the 12000g supernatant of these homogenates. 4. Homogenates produced by rupture of the tissue in an Ato-Mix blender and plastid preparations disintegrated by ultrasonic treatment both had fatty acid synthetase activity which did not sediment at 105000g and which formed mainly [14-C]stearate from [2-14C]malonyl-CoA. 5. It is concluded that the plastids are the principal site of fatty acid biosynthesis in the tissues studied.

Effect of Thiolactomycin on de novo Fatty Acid Biosynthesis in Plants

1990 ◽  
Vol 45 (5) ◽  
pp. 518-520 ◽  
Author(s):  
Manfred Focke ◽  
Andrea Feld ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Fatty Acid Synthetase ◽  
Acetate Incorporation ◽  
Acid Biosynthesis ◽  
Acetyl Coa ◽  
Malonyl Coa ◽  
Total Fatty Acids

Thiolactomycin was shown to be a potent inhibitor of de novo fatty acid biosynthesis in intact isolated chloroplasts (measured as [14C]acetate incorporation into total fatty acids). In our attempt to further localize the inhibition site we confirmed the inhibition with a fatty acid synthetase preparation, measuring the incorporation of [14C]malonyl-CoA into total fatty acids. From the two proposed enzymic targets of the fatty acid synthetase by thiolactomycin we could exclude the acetyl-CoA: ACP transacetylase. It appears that the inhibition by thiolactomycin occurs on the level of the condensing enzymes, i.e. the 3-oxoacyl-ACP synthases. We also demonstrated that the two starting enzymes of de novo fatty acid biosynthesis, the acetyl-CoA synthetase and the acetyl-CoA carboxylase, are not affected by thiolactomycin.

Évolution de la teneur en lipides de Leptosphaeria typhae en fonction de sa croissance et de sa reproduction sexuée : activité de synthèse et étude des lipides neutres et polaires

1985 ◽  
Vol 63 (12) ◽  
pp. 2460-2467
Author(s):  
Gérard Vidal
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Lipid Content ◽  
Neutral Lipids ◽  
Fatty Acid Synthetase ◽  
Polar Lipids ◽  
Synthetase Activity ◽  
Lipid Turnover ◽  
Fatty Acid Synthetase Activity

When perithecia appear (on the 7th day of growth), the mycelial lipid content falls and the degree of fat insaturation increases; fatty acid synthetase activity greatly increases. Lipid turnover is therefore accelerated. Among neutral lipids, triglycerides constitute the largest pool and their proportion increases when perithecia appear. Free fatty acids also increase, confirming the lipid turnover's acceleration. Polar lipids especially disappear; the phosphatidylcholine/phosphatidylethanolamine ratio increases when the fungus ascosporulates.

Notes: Inhibition of the Acetyl-CoA Carboxylase of Barley Chloroplasts by Cycloxydim and Sethoxydim

1987 ◽  
Vol 42 (11-12) ◽  
pp. 1361-1363 ◽  
Author(s):  
Manfred Focke ◽  
Hartmut K. Lichtenthaler
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Enzyme Preparation ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Acetyl Coa Carboxylase ◽  
Acid Biosynthesis ◽  
Hordeum Vulgare L ◽  
Acetyl Coa ◽  
Malonyl Coa

The effect of the three cyclohexane-1,3-dione derivatives cycloxydim, sethoxydim and clethodim on the incorpora­tion of 14C-labelled acetate, malonate. acctyl-CoA or malonyl-CoA into fatty acids was studied in an enzyme preparation isolated from barley chloroplasts (Hordeum vulgare L. var. “Alexis”). The herbicides cycloxydim, clethodim and sethoxydim block the de novo fatty acid biosynthesis from [2-14C]acetatc and [1-14C]acetyl-CoA, whereas that of [2-14C]malonatc and [2-14C)malonyl-CoA is not affected. The data indicate that the mode of action of the cyclohexane-1,3-dione derivatives in the sensitive bar­ley plant consists in the inhibition of de novo fatty acid biosynthesis by blocking the acetyl-CoA carboxylase (EC 6.4.1.2.).

scholarly journals Elongation of fatty acids by microsomal fractions from the brain of the developing rat

1975 ◽  
Vol 152 (3) ◽  
pp. 495-501 ◽  
Author(s):  
P J Brophy ◽  
D E Vance
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Brain ◽  
Microsomal Fraction ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Soluble Fraction ◽  
Residual Activity ◽  
Acid Biosynthesis ◽  
Malonyl Coa

Elongation of fatty acids by microsomal fractions obtained from rat brain was measured by the incorporation of [2-14C]malonyl-CoA into fatty in the presence of palmitoyl-CoA or stearoyl-CoA. 2. Soluble and microsomal fractions were prepared from 21-day-old rats; density gradient centrifugation demonstrated that the stearoyl-CoA elongation system was localized in the microsomal fraction whereas fatty acid biosynthesis de novo from acetyl-CoA occurred in the soluble fraction. The residual activity de novo in the microsomal fraction was attributed to minor contamination by the soluble fraction. 3. The optimum concentration of [2-14C]malonyl-CoA for elongation of fatty acids was 25 mum for palmitoyl-CoA or stearoyl-CoA, and the corresponding optimum concentrations for the two primer acyl-CoA esters were 8.0 and 7.2 muM respectively. 4. Nadph was the preferred cofactor for fatty acid formation from palmitoyl-CoA or stearoyl-CoA, although NADH could partially replace it. 5. The stearoyl-CoA elongation system required a potassium phosphate buffer concentration of 0.075M for maximum activity; CoA (1 MUM) inhibited this elongation system by approx. 30%. 6. The fatty acids formed from malonyl-CoA and palmitoyl-CoA had a predominant chain length of C18 whereas stearoyl-CoA elongation resulted in an even distribution of fatty acids with chain lengths of C20, C22 and C24. 7. The products of stearoyl-CoA elongation were identified as primarily unesterified fatty acids. 8. The developmental pattern of fatty acid biosynthesis by rat brain microsomal preparations was studied and both the palmitoyl-CoA and stearoyl-CoA elongation systems showed large increases in activity between days 10 and 18 after birth.

scholarly journals Genetic suppression of lethal mutations in fatty acid biosynthesis mediated by a secondary lipid synthase

2021 ◽  
Author(s):  
Marco N. Allemann ◽  
Eric E. Allen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Fatty Acid Synthase ◽  
Fatty Acid Biosynthesis ◽  
Biosynthetic Pathways ◽  
Omega 3 ◽  
Genetic Redundancy ◽  
Acid Biosynthesis ◽  
Malonyl Coa

The biosynthesis and incorporation of polyunsaturated fatty acids into phospholipid membranes is a unique feature of certain marine Gammaproteobacteria inhabiting high-pressure and/or low temperature environments. In these bacteria, monounsaturated and saturated fatty acids are produced via the classical dissociated Type II fatty acid synthase mechanism, while omega-3 polyunsaturated fatty acids such as EPA (20:5n-3) and DHA (22:6n-3) are produced by a hybrid polyketide/fatty acid synthase – encoded by the pfa genes - also referred to as the secondary lipid synthase mechanism. In this work, phenotypes associated with partial or complete loss of monounsaturated biosynthesis are shown to be compensated for by several-fold increased production of polyunsaturated fatty acids in the model marine bacterium Photobacterium profundum SS9. One route to suppression of these phenotypes could be achieved by transposition of insertion sequences within or upstream of the fabD, malonyl CoA-acyl carrier protein transacylase, coding sequence. Genetic experiments in this strain indicated that fabD is not an essential gene, yet mutations in fabD and pfaA are synthetically lethal. Based on these results, we speculated that the malonyl-CoA transacylase domain within PfaA compensates for loss of FabD activity. Heterologous expression of either pfaABCD from P. profundum SS9 or pfaABCDE from Shewanella pealeana in Escherichia coli complemented the loss of the chromosomal copy of fabD in vivo. The co-occurrence of independent, yet compensatory fatty acid biosynthetic pathways in select marine bacteria may provide genetic redundancy to optimize fitness under extreme conditions. Importance A defining trait among many cultured piezophilic and/or psychrophilic marine Gammaproteobacteria is the incorporation of both monounsaturated and polyunsaturated fatty acids into membrane phospholipids. The biosynthesis of these different classes of fatty acid molecules is linked to two genetically distinct co-occurring pathways that utilize the same pool of intracellular precursors. Using a genetic approach, new insights have been gained into the interactions between these two biosynthetic pathways. Specifically, core fatty acid biosynthesis genes previously thought to be essential were found to be non-essential in strains harboring both pathways due to functional overlap between the two pathways. These results provide new routes to genetically optimize long-chain omega-3 polyunsaturated fatty acid biosynthesis in bacteria and reveal a possible ecological role for maintaining multiple pathways for lipid synthesis in a single bacterium.

scholarly journals The same rat Δ6-desaturase not only acts on 18- but also on 24-carbon fatty acids in very-long-chain polyunsaturated fatty acid biosynthesis

2002 ◽  
Vol 364 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sabine D'ANDREA ◽  
Hervé GUILLOU ◽  
Sophie JAN ◽  
Daniel CATHELINE ◽  
Jean-Noël THIBAULT ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Chain Polyunsaturated Fatty Acid ◽  
Acid Biosynthesis ◽  
Highly Unsaturated Fatty Acids ◽  
Long Chain ◽  
Δ6 Desaturase

The recently cloned Δ6-desaturase is known to catalyse the first step in very-long-chain polyunsaturated fatty acid biosynthesis, i.e. the desaturation of linoleic and α-linolenic acids. The hypothesis that this enzyme could also catalyse the terminal desaturation step, i.e. the desaturation of 24-carbon highly unsaturated fatty acids, has never been elucidated. To test this hypothesis, the activity of rat Δ6-desaturase expressed in COS-7 cells was investigated. Recombinant Δ6-desaturase expression was analysed by Western blot, revealing a single band at 45kDa. The putative involvement of this enzyme in the Δ6-desaturation of C24:5n-3 to C24:6n-3 was measured by incubating transfected cells with C22:5n-3. Whereas both transfected and non-transfected COS-7 cells were able to synthesize C24:5n-3 by elongation of C22:5n-3, only cells expressing Δ6-desaturase were also able to produce C24:6n-3. In addition, Δ6-desaturation of [1-14C]C24:5n-3 was assayed invitro in homogenates from COS-7 cells expressing Δ6-desaturase or not, showing that Δ6-desaturase catalyses the conversion of C24:5n-3 to C24:6n-3. Evidence is therefore presented that the same rat Δ6-desaturase catalyses not only the conversion of C18:3n-3 to C18:4n-3, but also the conversion of C24:5n-3 to C24:6n-3. A similar mechanism in the n-6 series is strongly suggested.

SYNTHESIS OF FATTY ACIDS BY TESTICULAR TISSUE IN VITRO

1963 ◽  
Vol 41 (1) ◽  
pp. 1267-1274
Author(s):  
Peter F. Hall ◽  
Edward E. Nishizawa ◽  
Kristen B. Eik-Nes
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
De Novo ◽  
Fatty Acid Fraction ◽  
Testicular Tissue ◽  
Acid Biosynthesis ◽  
Adrenal Tissue ◽  
Substrate Fatty Acid

The fatty acids palmitic, palmitoleic, stearic, and oleic have been isolated from rabbit testis and evidence for the synthesis of palmitic and stearic acids de novo from acetate-1-C14is presented. ICSH did not produce demonstrable stimulation of the synthesis of these acids in vitro although the hormone stimulated the production of testosterone-C14by the same tissue. Adrenal tissue was shown to contain palmitic, stearic, and oleic acids, and ACTH did not increase the incorporation of acetate-1-C14into a fatty acid fraction extracted following incubation of adrenal tissue in the presence of this substrate. Fatty acid biosynthesis, therefore, is probably not influenced by the mechanisms by which tropic hormones increase steroid formation.

scholarly journals Fatty acid biosynthesis revisited: structure elucidation and metabolic engineering

2015 ◽  
Vol 11 (1) ◽  
pp. 38-59 ◽  
Author(s):  
Joris Beld ◽  
D. John Lee ◽  
Michael D. Burkart
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Metabolic Engineering ◽  
Structure Elucidation ◽  
Fatty Acid Biosynthesis ◽  
Acid Biosynthesis ◽  
Primary Metabolites ◽  
Biosynthetic Machinery

Fatty acids are primary metabolites synthesized by complex, elegant, and essential biosynthetic machinery.

Thiocarbamate Inhibition of Fatty Acid Biosynthesis in Isolated Spinach Chloroplasts

Weed Science ◽  
1975 ◽  
Vol 23 (2) ◽  
pp. 100-104 ◽  
Author(s):  
R. E. Wilkinson ◽  
A. E. Smith
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Biosynthesis ◽  
Spinacia Oleracea ◽  
Lipid Synthesis ◽  
Metabolic Effects ◽  
Acid Biosynthesis ◽  
Spinach Chloroplasts ◽  
Physiological Range

EPTC (S-ethyl dipropylthiocarbamate) (33μM) and diallate [S-(2,3-dichloroallyl)diisopropylthiocarbamate] (90μM) inhibited the incorporation of 6 mM acetate-2-14C (Ac∗) by 80% and 65%, respectively, and the incorporation of 0.5μM malonate-2-14C (Mal∗) by 32% and 26%, respectively, into the lipids of spinach (Spinacia oleraceaL.) chloroplasts. The inhibition of Ac∗or Mal∗incorporation into lipids was not observed in the presence of excess Ac∗or Mal∗, respectively. Incorporation of palmitate-1-14C and oleate-1-14C into chloroplast lipids was inhibited by EPTC and diallate. Mal∗incorporation into dienoic fatty acids was inhibited by EPTC and diallate. The concentration of EPTC and diallate inhibiting lipid synthesis falls into the physiological range of these herbicides, explains some metabolic effects of these compounds, and fits as the mode of activity of these herbicides.

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