ATP turnover by the fatty acid reductase complex of Photobacterium phosphoreum

1985 ◽  
Vol 63 (10) ◽  
pp. 1106-1111 ◽  
Author(s):  
Angel Rodriguez ◽  
Ivan R. Nabi ◽  
Edward Meighen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Atp Hydrolysis ◽  
Photobacterium Phosphoreum ◽  
Enzyme Complex ◽  
High Pressure Liquid Chromatographic ◽  
20 Nm ◽  
Liquid Chromatographic ◽  
Fold Stimulation ◽  
Stimulation Of

A sensitive reverse-phase high pressure liquid chromatographic assay for formation of AMP coupled with analysis of aldehyde production has been used to characterize the properties of the fatty acid reductase complex of Photobacterium phosphoreum. The enzyme complex, which consists of three different polypeptides (34 000, 50 000, and 58 000), has a high affinity for ATP (Km = 20 nM) and shows highest specificity with C14 fatty acids. Activation of the fatty acid is efficiently coupled to the reduction step showing a stoichiometry of one molecule of fatty acid reduced to aldehyde and one molecule of NADPH oxidized for every molecule of ATP converted to AMP. Reconstituted fatty acid reductase (50 000 and 58 000) shows an ATP hydrolase activity that is independent of NADPH with the maximum amount of AMP formed limited by the amount of fatty acid in the assay, consistent with acyl-protein turnover experiments and the channeling of fatty acids to form acyl thioesters (−NADPH) or aldehyde (+NADPH). Addition of the 34 000 polypeptide to the reconstituted enzyme results in stimulation of AMP formation (−NADPH) to a level far exceeding the amount of fatty acid, showing that the fatty acid can be recycled by the 34 000 protein through its thioesterase activity. Also the 34 000 protein is responsible for a two- to three-fold stimulation in the rate of ATP hydrolysis, suggesting that it can be involved in the stabilization of the enzyme complex.

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.

Effect of glucose concentration in the growth medium on the synthesis of fatty acids by the yeast Candida bogoriensis

1982 ◽  
Vol 28 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Adrian J. Cutler ◽  
Robley J. Light
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Yeast Extract ◽  
Fatty Acid Synthesis ◽  
Acid Synthesis ◽  
Glucose Medium ◽  
Triglyceride Fraction ◽  
Low Glucose ◽  
Stimulation Of

The yeast Candida bogoriensis produced large quantities of an extracellular glycolipid, the diacetyl sophoroside of 13-hydroxydocosanoic acid, when grown on a standard glucose rich medium (3% glucose, 0.15% yeast extract), but not when grown on a low glucose medium (0.5% glucose, 0.4% yeast extract) (A. J. Cutler and R. J. Light. 1979. J. Biol. Chem. 254: 1944–1950). Glucose levels also affected the quantity and distribution of the free fatty acid and triglyceride fractions synthesized by this organism. Cells grown on the low glucose medium contained palmitate and stearate as the major fatty acids in these two fractions, and a 3-h incubation with [1-14C]acetate led primarily to the labeling of these two acids. Cells grown on the standard enriched glucose medium contained relatively less stearate and more behenate than the low glucose grown cells, and the incorporation of [1-14C]acetate into stearate was decreased, while that into behenate was increased.Supplementation of low glucose grown cells with glucose led to a rapid stimulation of fatty acid synthesis, primarily palmitate and stearate in the free fatty acid fraction and stearate in the triglyceride fraction. Total triglyceride began to increase a few hours after supplementation, but synthesis of the extracellular glycolipid, and hence 13-hydroxydocosanoic acid, did not occur until 12–24 h after supplementation. The stimulation by glucose of long chain fatty acid synthesis in C. bogoriensis was therefore a process distinct from the glucose stimulation of palmitate and stearate synthesis, though the two events may be causally related.

scholarly journals Comparative Study on Quality Characteristics and Variations in Fatty Acid Composition of Different Varieties of Rapeseed and Mustard (Brassica spp.)

2018 ◽  
pp. 1-7
Author(s):  
Md. Delwar Hossain ◽  
Kamal Uddin Ahmed ◽  
Mst. Farhana Nazneen Chowdhury ◽  
Alak Barman ◽  
Arif Ahmed ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Erucic Acid ◽  
Acid Composition ◽  
Acid Value ◽  
Quality Characteristics ◽  
Brassica Spp ◽  
Liquid Chromatographic

With a view to studying the qualitative features and the variations in fatty acid composition of 6 rapeseed (B. campestris and B. napus) and mustard (B. juncea) varieties, an experiment was conducted. Among these varieties, BARI Sarisha-14 presented the value of 168.4 which was recorded the highest. Both BARI Sarisha-11 and BARI Sarisha-14 was found with the highest iodine value of 39.44; and the highest amount of acid value was recorded from BARI Sarisha-11 (1.867). Gas-liquid chromatographic (GLC) method has been used to determine the composition of essential fatty acid in the seeds of Brassica spp. (L.). From the GLC analysis, it was found that erucic acid, oleic acid, linoleic acid and lenolenic acid were the prime fatty acids in all the varieties. Erucic acid was in the range of 41.11 – 51.28%, oleic acid was the highest both in BARI Sarisha-11 and BARI Sarisha- 13 contained (18.69%), while BARI Sarisha-9 contained the highest amount of the unsaturated linoleic (17.75%)  and linolenic (15.83%) acids. Moreover, palmitic acid, stearic acid and archidic acid were also present in small amount.

Stimulation of Strontium Accumulation in Linoleate-Enriched Saccharomyces cerevisiae Is a Result of Reduced Sr2+ Efflux

1999 ◽  
Vol 65 (3) ◽  
pp. 1191-1197 ◽  
Author(s):  
Simon V. Avery ◽  
Shareeka L. Smith ◽  
A. Mohamad Ghazi ◽  
Michael J. Hoptroff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Plasma Membrane ◽  
Fatty Acid ◽  
Atpase Inhibitor ◽  
Calmodulin Antagonist ◽  
Wide Range ◽  
Fatty Acid Supplement ◽  
Accumulation Ability ◽  
Stimulation Of

ABSTRACT The influence of modified plasma membrane fatty acid composition on cellular strontium accumulation in Saccharomyces cerevisiaewas investigated. Growth of S. cerevisiae in the presence of 1 mM linoleate (18:2) (which results in 18:2 incorporation to ∼70% of total cellular and plasma membrane fatty acids, with no effect on growth rate) yielded cells that accumulated Sr2+ intracellularly at approximately twice the rate ofS. cerevisiae grown without a fatty acid supplement. This effect was evident over a wide range of external Sr2+concentrations (25 μM to 5 mM) and increased with the extent of cellular 18:2 incorporation. Stimulation of Sr2+accumulation was not evident following enrichment of S. cerevisiae with either palmitoleate (16:1), linolenate (18:3) (n-3 and n-6 isomers), or eicosadienoate (20:2) (n-6 and n-9 isomers). Competition experiments revealed that Ca2+- and Mg2+-induced inhibition of Sr2+ accumulation did not differ between unsupplemented and 18:2-supplemented cells. Treatment with trifluoperazine (TFP) (which can act as a calmodulin antagonist and Ca2+-ATPase inhibitor), at a low concentration that precluded nonspecific K+ efflux, increased intracellular Sr2+ accumulation by approximately 3.6- and 1.4-fold in unsupplemented and 18:2-supplemented cells, respectively. Thus, TFP abolished the enhanced Sr2+ accumulation ability of 18:2-supplemented cells. Moreover, the rate of Sr2+release from Sr2+-loaded fatty acid-unsupplemented cells was found to be at least twice as great as that from Sr2+-loaded 18:2-enriched cells. The influence of enrichment with other fatty acids on Sr2+ efflux was variable. The results reveal an enhanced Sr2+ accumulation ability of S. cerevisiae following 18:2-enrichment, which is attributed to diminished Sr2+ efflux activity in these cells.

Extremely rapid effects of polyunsaturated fatty acids and N-acetylglucosamine on free-radical metabolism in cultured potato plant cells

2000 ◽  
Vol 28 (6) ◽  
pp. 865-867 ◽  
Author(s):  
P. A. Kashulin ◽  
M. N. Merzlyak ◽  
P. M. Zhiboedov ◽  
V. K. Zhirov
Keyword(s):  
Fatty Acids ◽  
Solanum Tuberosum ◽  
Fatty Acid ◽  
Free Radical ◽  
Cell Cultures ◽  
Plant Cells ◽  
Dichlorofluorescin Diacetate ◽  
Radical Generation ◽  
Defensive Mechanisms ◽  
Stimulation Of

The effects of arachidonic and linoleic acids, separately and in co-operation with N-acetylglucosamine oligomers, on Solanum tuberosum plant suspension cell cultures were investigated in terms of the fluorescent oxygen-activated-species-sensitive dye 2Î,7Î-dichlorofluorescin diacetate. The inductors used triggered extremely rapid (within 2–10 min) generation of H2O2 in the cells; the majority was expressed in cultures treated with combined polyunsaturated fatty acid and N-acetylglucosamine oligomers. The stimulation of free-radical generation may be related to defensive mechanisms modulating a plant-pathogenicmicro-organism interaction.

Eicosapentaenoic and dihomo gamma linolenic acid metabolism by cultured rat mesangial cells

1989 ◽  
Vol 256 (1) ◽  
pp. C101-C108 ◽  
Author(s):  
L. A. Scharschmidt ◽  
N. B. Gibbons ◽  
R. Neuwirth
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Metabolism ◽  
Mesangial Cells ◽  
Gamma Linolenic Acid ◽  
Significant Extent ◽  
Glomerular Function ◽  
Fatty Acid Release ◽  
Acid Release ◽  
Stimulation Of

To better understand the effects of dietary fatty acid manipulations on glomerular function, we compared mesangial incorporation, release, and metabolism of arachidonic (AA), eicosapentaenoic (EPA), and dihomo gamma linolenic (DHG) acids. We found marked differences in mesangial handling of these fatty acids. AA was incorporated into lipids of mesangial cells much more rapidly than EPA or DHG. Ionophore-induced stimulation of fatty acid release from mesangial cells prelabeled with [14C]AA, [14C]EPA, or [14C]DHG caused a release of labeled AA greater than DHG much less than EPA, respectively. Preloading mesangial cells with DHG or EPA for 24 h reduced subsequent basal, ionophore-, and hormone-stimulated prostaglandin E2 (PGE2) synthesis. Finally, unlike AA, neither EPA nor DHG was converted to a significant extent by mesangial cyclooxygenase or lipoxygenase. Thus the mesangial metabolism of DHG and EPA differs both quantitatively and qualitatively from that of AA. Furthermore, EPA and DHG inhibit metabolism of AA at the level of mesangial cyclooxygenase.

scholarly journals Chemical modification of sarcoplasmic reticulum with methylbenzimidate. Stimulation of Ca2+ efflux

1987 ◽  
Vol 243 (1) ◽  
pp. 165-173 ◽  
Author(s):  
V Shoshan-Barmatz
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Chemical Modification ◽  
Atp Hydrolysis ◽  
Divalent Cations ◽  
Protein Factor ◽  
Time Period ◽  
Fold Stimulation ◽  
Stimulation Of

Treatment of sarcoplasmic reticulum membranes with 12 mM-methylbenzimidate (MBI) for 5 min, in the presence of 5 mM-ATP at pH 8.5, resulted in a 2-3-fold stimulation of ATP hydrolysis and over 90% inhibition of Ca2+ accumulation. This phenomenon was strictly dependent upon the presence of nucleotides with the following order of effectiveness: adenosine 5′-[beta, gamma-imido]triphosphate greater than or equal to ATP greater than UTP greater than ADP greater than AMP. Divalent cations such as Ca2+, Mg2+ and Mn2+, when present during the MBI treatment, prevented both the stimulation of ATPase activity and the inhibition of Ca2+ accumulation. Modification with MBI had no effect on E-P formation from ATP, ADP-ATP exchange, Ca2+ binding or ATP-Pi exchange catalysed by the membranes. Membranes modified with MBI in the presence of ATP and then passively loaded with Ca2+ released about 80% of their Ca2+ content within 3 s. Control membranes released only 3% of their Ca2+ during the same time period. MBI modification inhibited Ca2+ accumulation by proteoliposomes reconstituted with the partially purified ATPase but not with the purified ATPase fraction. These results suggest that MBI in the presence of ATP stimulates Ca2+ release by modifying a protein factor(s) other than the (Ca2+ + Mg2+)-ATPase.

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