Inhibition of Fatty Acid Synthetase in Halobacterium cutirubrum and Escherichia coli by High Salt Concentrations

1971 ◽  
Vol 49 (8) ◽  
pp. 953-958 ◽  
Author(s):  
E. L. Pugh ◽  
M. K. Wassef ◽  
M. Kates
Keyword(s):  
Fatty Acid ◽  
Sodium Chloride ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
Chloride Concentration ◽  
High Sodium ◽  
E Coli ◽  
Level Of Activity ◽  
Malonyl Coa ◽  
A Cell

A cell-free enzyme preparation from Halobacterium cutirubrum was shown to catalyze the biosynthesis of fatty acids from malonyl-CoA at zero sodium chloride concentration, with a specific activity about [Formula: see text] that of a similarly prepared fatty acid synthetase from E. coli. Both the H. cutirubrum synthetase and that from E. coli were strongly inhibited by high sodium chloride or potassium chloride concentrations (0.5–4 M). The malonyl-CoA: ACP transacylase, which catalyzes the first step in the fatty acid biosynthetic pathway, was shown to be strongly inhibited by salt in H. cutirubrum, but not in E. coli. It is concluded that H. cutirubrum contains a fatty acid synthetase system which normally operates at a very low level of activity as a result of inhibition by the high intracellular salt concentration present in this organism.

scholarly journals Stoichiometry of substrate binding to rat liver fatty acid synthetase

1985 ◽  
Vol 230 (2) ◽  
pp. 435-440 ◽  
Author(s):  
J Mikkelsen ◽  
S Smith ◽  
A Stern ◽  
J Knudsen
Keyword(s):  
Fatty Acid ◽  
Rat Liver ◽  
Specific Activity ◽  
Substrate Binding ◽  
Fatty Acid Synthetase ◽  
Liver Fatty Acid ◽  
Acetyl Coa ◽  
Malonyl Coa ◽  
Symmetrical Model ◽  
Active Centres

Two rat liver fatty acid synthetase preparations, containing 1.6 and 2.0 mol of 4′-phosphopantetheine/mol of synthetase, showed specific activity of 2006 and 2140 nmol of NADPH oxidized/min per mg of protein respectively. The two synthetase preparations could be loaded with either 3.3-4.4 mol of [1–14] acetate or 2.9-3.7 mol of [2-14C]malonate, by incubation with either [1-14C] acetyl-CoA or [2-14C]malonyl-CoA. The 4′-phosphopantetheine site could be more than 90% saturated and the serine site about 80% saturated with malonate derived from malonyl-CoA. However, with acetyl-CoA as substrate, binding at both the 4′-phosphopantetheine and cysteine thiol sites did not reach saturation. We interpret these results to indicate that, whereas the equilibrium constant for transfer of substrates between the serine loading site and the 4′-phosphopantetheine site is close to unity, that for transfer of acetyl moieties between the 4′-phosphopantetheine and cysteine sites favours formation of the 4′-phosphopantetheine thioester. Thus, despite the apparent sub-stoichiometric binding of acetate, the results are consistent with a functionally symmetrical model for the fatty acid synthetase which permits simultaneous substrate binding at two separate active centres.

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.

TURBIDITY OF SUSPENSIONS AND MORPHOLOGY OF RED HALOPHILIC BACTERIA AS INFLUENCED BY SODIUM CHLORIDE CONCENTRATION

1960 ◽  
Vol 6 (5) ◽  
pp. 535-543 ◽  
Author(s):  
Dinah Abram ◽  
N. E. Gibbons
Keyword(s):  
Sodium Chloride ◽  
Salt Concentration ◽  
Morphological Changes ◽  
Halophilic Bacteria ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Wall Structure ◽  
Abrupt Decrease ◽  
High Sodium ◽  
Rigid Cell Wall

The optical densities of suspensions of cells of Halobacterium cutirubrum, H. halobium, or H. salinarium, grown in media containing 4.5 M sodium chloride, increase as the salt concentration of the suspending medium decreases, until a maximum is reached at about 2 M; below this concentration there is an abrupt decrease in optical density. The cells are rod shaped in 4.5 M salt and change, as the salt concentration decreases, through irregular transition forms to spheres; equal numbers of transition forms and spheres are present at the point of maximum turbidity, while spheres predominate at lower salt concentrations. Cells suspended in 3.0 M salt, although slightly swollen, are viable, but viability decreases rapidly with the more drastic changes in morphology at lower salt concentrations. Cells grown in the presence of iron are more resistant to morphological changes but follow the same sequence. Cells "fixed" with formaldehyde, at any point in the sequence, act as osmometers and do not rupture in distilled water although their volume increases 10–14 times. The results indicate that the red halophilic rods require a high sodium chloride content in their growth or suspending medium to maintain a rigid cell wall structure.

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.

scholarly journals Increase in fatty acid synthetase content of 3T3-L cells undergoing spontaneous and chemically induced differentiation to adipocytes

1979 ◽  
Vol 182 (2) ◽  
pp. 509-514 ◽  
Author(s):  
P M Ahmad ◽  
T R Russell ◽  
F Ahmad
Keyword(s):  
Fatty Acid ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
L Cells ◽  
Differentiated Cells ◽  
Cellular Content ◽  
Chemically Induced ◽  
Low Incidence ◽  
Continuous Presence ◽  
Adipose Cells

3T3-L fibroblasts differentiate into adipose cells when maintained in a non-growing state. The specific activity of fatty acid synthetase of differentiated cells was 25–30-fold higher than that present in 3T3-L fibroblasts or in 3T3-C2 cells that possess an extremely low incidence of differentiation to adipocytes. The results of immunochemical analysis indicate that the increased specific activity of fatty acid synthetase in the differentiated cells is due to an increase in the cellular content of this enzyme. The rate of conversion of adipose cells was accelerated by brief exposure of confluent non-growing cultures of 3T3-L cells to 3-isobutyl-1-methylxanthine. This was accompanied by an increase in the specificity activity of fatty acid synthetase, which was also shown to be due to an increase in the cellular content of this enzyme. The continuous presence of 3-isobutyl-1-methylxanthine in the culture medium was not required to elicit the morphological and biochemical changes in 3T3-L cells that occurred many days after the removal of the inducer but earlier than the onset of spontanous differentiation.

scholarly journals Effect of phenylpyruvate on enzymes involved in fatty acid synthesis in rat brain

1973 ◽  
Vol 134 (2) ◽  
pp. 545-555 ◽  
Author(s):  
John M. Land ◽  
John B. Clark
Keyword(s):  
Fatty Acid ◽  
Citrate Synthase ◽  
Mitochondrial Protein ◽  
Fatty Acid Synthetase ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Adult Rats ◽  
Malonyl Coa ◽  
Old Rats ◽  
The Brain

1. The activities of, and the effects of phenylpyruvate on, citrate synthase (EC 4.1.3.7), acetyl-CoA carboxylase (EC 6.4.1.2) and fatty acid synthetase derived from the brains of 14-day-old and adult rats were investigated. 2. The brain citrate synthase from 14-day-old rats had a Km for oxaloacetate of 2.38μm and for acetyl-CoA of 16.9μm, and a Vmax. of 838nmol of acetyl-CoA incorporation/min per mg of mitochondrial protein. From adult rat brain this enzyme had a Km for oxaloacetate of 2.5μm and for acetyl-CoA of 16.6μm and a Vmax. of 1070nmol of acetyl-CoA incorporated/min per mg of mitochondrial protein. Phenylpyruvate inhibited the enzyme from adult and young rat brains in a competitive fashion with respect to acetyl-CoA, with a Ki of 700μm. 3. The brain acetyl-CoA carboxylase from 14-day-old rats had a Km for acetyl-CoA of 21μm and a Vmax. of 0.248nmol/min per mg of protein, and from adult rats a Km for acetyl-CoA of 21μm and a Vmax. of 0.173nmol/min per mg of protein. The enzyme from young and adult rats required citrate (Ka=3mm) for activation and were inhibited non-competitively by phenylpyruvate, with a Ki of 10mm. 4. The brain fatty acid synthetase from 14-day-old rats had a Km for acetyl-CoA of 7.58μm and a Vmax. of 1.1 nmol of malonyl-CoA incorporated/min per mg of protein, and from adult rats a Km for acetyl-CoA of 4.9μm and a Vmax. of 0.48nmol of malonyl-CoA incorporated/min per mg of protein. Phenylpyruvate acted as a competitive inhibitor with respect to acetyl-CoA with a Ki of 250μm for the enzyme from 14-day-old rats. 5. These results are discussed with respect to phenylketonuria, and it is suggested that the inhibition of the brain fatty acid synthetase and possibly the citrate synthetase by phenylpyruvate could explain the defective myelination characteristic of this condition.

Antibacterial Action of Vinegar against Food-Borne Pathogenic Bacteria Including Escherichia coliO157:H7

1998 ◽  
Vol 61 (8) ◽  
pp. 953-959 ◽  
Author(s):  
ETSUZO ENTANI ◽  
MITO ASAI ◽  
SHIGETOMO TSUJIHATA ◽  
YOSHINORI TSUKAMOTO ◽  
MICHIO OHTA
Keyword(s):  
Acetic Acid ◽  
Sodium Chloride ◽  
Growth Phase ◽  
Pathogenic Bacteria ◽  
Chloride Concentration ◽  
Inactivation Rate ◽  
Viable Cell Number ◽  
Logarithmic Growth Phase ◽  
E Coli ◽  
Food Borne

The bacteriostatic and bactericidal actions of vinegar on food-borne pathogenic bacteria including enterohemorrhagic E. coli (EHEC) O157:H7 were examined. The growth of all strains evaluated was inhibited with a 0.1% concentration of acetic acid in the vinegar. This inhibition was generally increased in the presence of sodium chloride or glucose. There was almost no difference in sensitivity to the bacteriostatic action of vinegar among the strains of pathogenic E. coli. Vinegar had a bactericidal effect on food-borne pathogenic bacteria including EHEC O157:H7. This action against EHEC O157:H7 was synergically enhanced by sodium chloride but was attenuated with glucose. For EHEC strains (O157:H7, O26:H11, O111:HNM) the difference in the inactivation rate due to vinegar among strains used was small, although an enteropathogenic E. coli (EPEC) O111:K58:H− strain was more sensitive, being more quickly killed compared with EHEC strains. The inactivation rate due to vinegar was constant irrespective of inoculum size. However, it differed greatly depending on growth phase of the cells, where logarithmic growth phase cells were more sensitive and easily killed than stationary phase cells. The bactericidal activity of vinegar increased with the temperature. Various conditions for bactericidal effects on EHEC O157:H7 were examined by the multiparametric analysis of five factors: acetic acid concentration in the vinegar, sodium chloride concentration, temperature, incubation time, and viable cell number. The combined use of vinegar and sodium chloride, with use of an appropriate treatment temperature, was found to be markedly effective for the prevention of bacterial food poisoning.

Effects of glucocorticoid hormones on lipid-synthetic enzymes from different adipose tissue regions and from liver

1983 ◽  
Vol 61 (12) ◽  
pp. 1245-1250 ◽  
Author(s):  
David C. W. Lau ◽  
Daniel A. K. Roncari
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Specific Activity ◽  
Fatty Acid Synthetase ◽  
Subcellular Fractions ◽  
Fat Tissue ◽  
Synthetic Enzymes ◽  
Regional Effects ◽  
Fat Depots ◽  
Adipose Tissue Depots

The regional diversity of adipose tissue is dramatically accentuated in states of glucocorticoid excess, in which certain fat depots expand, while others contract. We have studied the molecular basis of this redistribution by determining the activity of fatty acid synthetase and enzymes catalyzing di- and tri-acylglycerol synthesis, in subcellular fractions from four adipose depots of rats injected with dexamethasone and from interscapular and epididymal adipocyte precursors after addition of either dexamethasone or corticosterone to confluent monolayers in secondary culture. Subcellular fractions from cervical and interscapular adipose tissue, as well as from cultured interscapular precursors, revealed a general increase in specific enzyme activity. The opposite trend was observed for retroperitoneal and epididymal fat tissue, as well as cultured epididymal precursors. Fatty acid synthetase and cytosolic phosphatidate phosphohydrolase appeared to be most responsive. The findings in culture indicate that the regional effects of glucocorticoids are partly independent of other circulating or neural factors. Injections of dexamethasone led to significantly enhanced specific activity of all the lipid-synthetic enzymes assayed in subcellular fractions from liver. Differences in hormonal influences between liver and certain fat tissue regions represent tissue specificity. In addition, the diverse effects of glucocorticoids on various adipose tissue depots indicate regional or "intratissue" specificity.

Effect of E. coli endotoxin on the structure-function of fatty acid synthetase lipoprotein

1981 ◽  
Vol 101 (4) ◽  
pp. 1228-1232 ◽  
Author(s):  
J.G. Gavilanes ◽  
M.A. Lizarbe ◽  
A.M. Municio ◽  
M. Oñaderra
Keyword(s):  
Fatty Acid ◽  
Structure Function ◽  
Fatty Acid Synthetase ◽  
E Coli
Sign in / Sign up

Export Citation Format

Share Document