Specific inhibition of iturin biosynthesis by cerulenin

1990 ◽  
Vol 36 (3) ◽  
pp. 164-168 ◽  
Author(s):  
Marie-Laure Hourdou ◽  
Françoise Besson ◽  
Georges Michel
Keyword(s):  
Fatty Acids ◽  
Protein Synthesis ◽  
Bacillus Subtilis ◽  
Fatty Acid ◽  
Amino Acid ◽  
Fatty Acid Synthesis ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Specific Inhibition ◽  
Malonyl Coa

Cerulenin, an inhibitor of fatty acid synthesis, inhibits the biosynthesis of iturin by Bacillus subtilis. With a cerulenin concentration of 2 μg/mL, 50% inhibition was achieved. At this concentration, cerulenin does not affect growth or total protein synthesis but does inhibit the incorporation of sodium [14C]acetate, [14C]myristic acid, and [14C]asparagine into iturin. Since cerulenin is known to block the condensation of malonyl-CoA subunits in the formation of fatty acids, the inhibition of iturin and β-amino acid syntheses by cerulenin is discussed in relation with lipid synthesis. Key words: iturin antibiotic, Bacillus subtilis, cerulenin, β-amino acid, lipid biosynthesis.

scholarly journals Medium-chain fatty acids as short-term regulators of hepatic lipogenesis

1994 ◽  
Vol 302 (1) ◽  
pp. 141-146 ◽  
Author(s):  
M J H Geelen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
Short Term ◽  
Acetyl Coa ◽  
Carboxylase Activity ◽  
Malonyl Coa ◽  
Stimulation Of

Short-term exposure of isolated rat hepatocytes to short- and medium-chain fatty acids led to an activation of acetyl-CoA carboxylase as measured in digitonin-permeabilized hepatocytes. Up to a certain concentration, typical for each of the fatty acids used, fatty acid-dependent activation of acetyl-CoA carboxylase coincided with an increase in the rate of fatty acid synthesis in intact hepatocytes, as determined by the incorporation of 3H from 3H2O water into fatty acids. At higher concentrations loss of stimulation of fatty acid synthesis occurred, but not the enhancement of carboxylase activity. With the fatty acids tested (C8:0-C14:0), the peak in fatty acid synthesis coincided with a peak in the level of malonyl-CoA. The onset of the stimulation of carboxylase activity coincided with the start of the peak in both fatty acid synthesis and malonyl-CoA. The longer the chain length of the fatty acid added, the lower the concentration at which the rate of fatty acid synthesis and the level of malonyl-CoA reached a peak and carboxylase activity started to become elevated. In cell suspensions incubated with increasing concentrations of fatty acids, accumulation of lactate decreased progressively. The latter observation, in combination with the fact that the activity of acetyl-CoA carboxylase is not always related to the rate of fatty acid biosynthesis, suggests that under these conditions not the activity of the carboxylase but the flux through the glycolytic sequence determines, at least in part, the rate of fatty acid synthesis de novo.

scholarly journals Utilization of methylmalonate for the synthesis of branched-chain fatty acids by preparations of chicken liver and sheep adipose tissue

1978 ◽  
Vol 176 (3) ◽  
pp. 799-804 ◽  
Author(s):  
J R Scaife ◽  
K W J Wahle ◽  
G A Garton
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Complex Mixture ◽  
Acid Synthesis ◽  
Inhibitory Effect ◽  
Chicken Liver ◽  
Malonyl Coa ◽  
Branched Chain

1. The utilization of methyl[2-14C]malonyl-CoA for fatty acid synthesis was investigated using synthetase preparations from chicken liver and sheep adipose tissue. 2. The rate of fatty acid synthesis from acetyl-CoA and malonyl-CoA was greatly diminished in the presence of methylmalonyl-CoA. 3. In the absence of malonyl-CoA, methylmalonyl-CoA was utilized for fatty acid synthesis only very slowly by the synthetase from sheep adipose tissue and not at all by that from chicken liver. 4. Despite the inhibitory effect of methylmalonyl-CoA on fatty acid synthesis from malonyl-CoA, it was utilized by the synthetase preparations from both species to produce a complex mixture of methyl-branched fatty acids.

The Classical, Yet Controversial, First Enzyme of Lipid Synthesis: Escherichia coli Acetyl-CoA Carboxylase

2021 ◽  
Author(s):  
John E. Cronan
Keyword(s):  
Escherichia Coli ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Building Block ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Content Type ◽  
Malonyl Coa

SUMMARY Escherichia coli acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of the malonyl-CoA, the building block of fatty acid synthesis, is the paradigm bacterial ACC. Many reports on the structures and stoichiometry of the four subunits comprising the active enzyme as well as on regulation of ACC activity and expression have appeared in the almost 20 years since this subject was last reviewed. This review seeks to update and expand on these reports.

Contribution of pentose phosphate pathway in developing castor bean endosperm

1971 ◽  
Vol 49 (2) ◽  
pp. 267-272 ◽  
Author(s):  
P. K. Agrawal ◽  
D. T. Canvin
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Pentose Phosphate Pathway ◽  
Castor Bean ◽  
Lipid Synthesis ◽  
Experimental Period ◽  
Acid Synthesis ◽  
Pentose Phosphate ◽  
Fat Synthesis

Glucose-1-14C, glucose-6-14C, and glucose-U-14C were used to calculate the contribution of the PPP in developing castor bean endosperm tissues. Depending on the age of the seed 5–12% of the glucose-14C used was metabolized via the PPP and 88–95% via the EMP pathway. When lipid synthesis was rapid (20- to 28-day period) the PPP contribution was also at a maximum. During the 30- to 51-day period when lipid synthesis decreased so did the PPP contribution.With the data obtained from the PPP contribution the amount of NADPH produced during the experimental period was calculated. Also, the amount of fatty acids synthesized during that period was determined from glucose-U-14C data and thus the amount of NADPH required was calculated. Assuming that all the NADPH produced in the PPP was utilizable in fatty acid synthesis it was found that it was only sufficient to supply 50–75% of the reducing hydrogen required for fat synthesis. Therefore, the rest of the reducing hydrogen must come from some other sources, possibly NADH.

scholarly journals Coupling of Fatty Acid and Phospholipid Synthesis in Bacillus subtilis

2007 ◽  
Vol 189 (16) ◽  
pp. 5816-5824 ◽  
Author(s):  
Luciana Paoletti ◽  
Ying-Jie Lu ◽  
Gustavo E. Schujman ◽  
Diego de Mendoza ◽  
Charles O. Rock
Keyword(s):  
Fatty Acids ◽  
Bacillus Subtilis ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Conditional Knockout ◽  
Acid Formation ◽  
Acyl Donor ◽  
Phospholipid Synthesis ◽  
Membrane Phospholipids

ABSTRACT plsX (acyl-acyl carrier protein [ACP]:phosphate acyltransferase), plsY (yneS) (acyl-phosphate:glycerol-phosphate acyltransferase), and plsC (yhdO) (acyl-ACP:1-acylglycerol-phosphate acyltransferase) function in phosphatidic acid formation, the precursor to membrane phospholipids. The physiological functions of these genes was inferred from their in vitro biochemical activities, and this study investigated their roles in gram-positive phospholipid metabolism through the analysis of conditional knockout strains in the Bacillus subtilis model system. The depletion of PlsX led to the cessation of both fatty acid synthesis and phospholipid synthesis. The inactivation of PlsY also blocked phospholipid synthesis, but fatty acid formation continued due to the appearance of acylphosphate intermediates and fatty acids arising from their hydrolysis. Phospholipid synthesis ceased following PlsC depletion, but fatty acid synthesis continued at a high rate, leading to the accumulation of fatty acids arising from the dephosphorylation of 1-acylglycerol-3-P followed by the deacylation of monoacylglycerol. Analysis of glycerol 3-P acylation in B. subtilis membranes showed that PlsY was an acylphosphate-specific acyltransferase, whereas PlsC used only acyl-ACP as an acyl donor. PlsX was found in the soluble fraction of disrupted cells but was associated with the cell membrane in intact organisms. These data establish that PlsX is a key enzyme that coordinates the production of fatty acids and membrane phospholipids in B. subtilis.

scholarly journals The regulation of glyceride synthesis in isolated white-fat cells. The effects of palmitate and lipolytic agents

1972 ◽  
Vol 128 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
E. D Saggerson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Fat Cells ◽  
Glyceride Synthesis ◽  
Glucose Incorporation ◽  
High Concentrations ◽  
Stimulation Of

1. 0.5mm-Palmitate stimulated incorporation of [U-14C]glucose into glyceride glycerol and fatty acids in normal fat cells in a manner dependent upon the glucose concentration. 2. In the presence of insulin the incorporation of 5mm-glucose into glyceride fatty acids was increased by concentrations of palmitate, adrenaline and 6-N-2′-O-dibutyryladenosine 3′:5′-cyclic monophosphate up to 0.5mm, 0.5μm and 0.5mm respectively. Higher concentrations of these agents produced progressive decreases in the rate of glucose incorporation into fatty acids. 3. The effects of palmitate and lipolytic agents upon the measured parameters of glucose utilization were similar, suggesting that the effects of lipolytic agents are mediated through increased concentrations of free fatty acids. 4. In fat cells from 24h-starved rats, maximal stimulation of glucose incorporation into fatty acids was achieved with 0.25mm-palmitate. Higher concentrations of palmitate were inhibitory. In fat cells from 72h-starved rats, palmitate only stimulated glucose incorporation into fatty acids at high concentrations of palmitate (1mm and above). 5. The ability of fat cells to incorporate glucose into glyceride glycerol in the presence of palmitate decreased with increasing periods of starvation. 6. It is suggested that low concentrations of free fatty acids stimulate fatty acid synthesis from glucose by increasing the utilization of ATP and cytoplasmic NADH for esterification of these free fatty acids. When esterification of free fatty acids does not keep pace with their provision, inhibition of fatty acid synthesis occurs. Provision of free fatty acids far in excess of the esterification capacity of the cells leads to uncoupling of oxidative phosphorylation and a secondary stimulation of fatty acid synthesis from glucose.

scholarly journals Modulation of lipid-synthesizing enzymes by insulin in differentiated ob17 adipose-like cells

1983 ◽  
Vol 214 (2) ◽  
pp. 443-449 ◽  
Author(s):  
P Grimaldi ◽  
C Forest ◽  
P Poli ◽  
R Negrel ◽  
G Ailhaud
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
Lipid Synthesis ◽  
Acid Synthesis ◽  
Acetate Incorporation ◽  
Long Term Effects ◽  
Response Curves ◽  
Glycerol 3 Phosphate Dehydrogenase

ob17 cells convert into adipose-like cells when maintained in the presence of physiological concentrations of insulin and tri-iodothyronine. After this conversion, insulin removal from differentiated ob17 cells gives within 24-48 h a large decrease in fatty acid synthetase, glycerol 3-phosphate dehydrogenase and acid:CoA ligase activities, as well as in the rate of fatty acid synthesis determined by [14C]acetate incorporation into lipids. All parameters are restored by insulin addition to initial values within 24-48 h. Dose-response curves of insulin on the restoration of glycerol 3-phosphate dehydrogenase activity and of fatty acid synthesis give half-maximally effective concentrations close to 1 nM, in agreement with the affinity for insulin of the insulin receptors previously characterized in these cells. Immunotitration experiments indicate that the changes in the specific activity of fatty acid synthetase are due to parallel changes in the cellular enzyme content. Therefore the ob17 cell line should be a useful model to study the long-term effects of insulin on the modulation of lipid synthesis in adipose cells.

scholarly journals Synthesis of fatty acids in the perfused mouse liver

1974 ◽  
Vol 142 (3) ◽  
pp. 611-618 ◽  
Author(s):  
D. Michael W. Salmon ◽  
Neil L. Bowen ◽  
Douglas A. Hems
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Saturated Fatty Acids ◽  
Carbon Sources ◽  
Acid Synthesis ◽  
Hepatic Glycogen ◽  
Total Rate ◽  
Glucose Carbon

1. Fatty acid synthesis de novo was measured in the perfused liver of fed mice. 2. The total rate, measured by the incorporation into fatty acid of3H from3H2O (1–7μmol of fatty acid/h per g of fresh liver), resembled the rate found in the liver of intact mice. 3. Perfusions with l-[U-14C]lactic acid and [U-14C]glucose showed that circulating glucose at concentrations less than about 17mm was not a major carbon source for newly synthesized fatty acid, whereas lactate (10mm) markedly stimulated fatty acid synthesis, and contributed extensive carbon to lipogenesis. 4. The identification of 50% of the carbon converted into newly synthesized fatty acid lends further credibility to the use of3H2O to measure hepatic fatty acid synthesis. 5. The total rate of fatty acid synthesis, and the contribution of glucose carbon to lipogenesis, were directly proportional to the initial hepatic glycogen concentration. 6. The proportion of total newly synthesized lipid that was released into the perfusion medium was 12–16%. 7. The major products of lipogenesis were saturated fatty acids in triglyceride and phospholipid. 8. The rate of cholesterol synthesis, also measured with3H2O, expressed as acetyl residues consumed, was about one-fourth of the basal rate of fatty acid synthesis. 9. These results are discussed in terms of the carbon sources of hepatic newly synthesized fatty acids, and the effect of glucose, glycogen and lactate in stimulating lipogenesis, independently of their role as precursors.

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