Inhibition of early steps of de novo fatty-acid biosynthesis by different xenobiotica

1991 ◽  
Vol 81 (2) ◽  
pp. 251-255
Author(s):  
Manfred Focke ◽  
Andrea Feld ◽  
Hartmut K. Lichtenthaler
1992 ◽  
Vol 47 (5-6) ◽  
pp. 382-386 ◽  
Author(s):  
Bernd List ◽  
Andrea Golz ◽  
Wilhelm Boland ◽  
Hartmut K. Lichtenthaler

The antibiotic cerulenin was shown to be a potent dose-dependent inhibitor of de novo fattyacid biosynthesis in intact isolated chloroplasts of different plants (measured as [14C]acetate incorporation into the total fatty-acid fraction). Various chemical derivatives of cerulenin were synthesized and tested in the chloroplast assay-system of oat, spinach and pea. Modifications of the hydrocarbon chain of cerulenin (e.g. tetrahydro-cerulenin and its short-chain cis-2,3-epoxy-4-oxoheptanamide derivative) decreased the inhibitory activity of cerulenin, whereas variations of the epoxy-oxo-amide structural element led to a complete loss of inhibition potency. The results indicate that the naturally occurring antibiotic cerulenin is the most active specific inhibitor of de novo fatty-acid biosynthesis, but the formation of the hydroxylactam ring seems to be an essential requirement for the inhibitory activity. Those structural analogues of cerulenin, which can no longer form a hydroxylactam ring, do not possess any inhibitory capacity.


1963 ◽  
Vol 41 (1) ◽  
pp. 1267-1274
Author(s):  
Peter F. Hall ◽  
Edward E. Nishizawa ◽  
Kristen B. Eik-Nes

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.


1990 ◽  
Vol 45 (5) ◽  
pp. 518-520 ◽  
Author(s):  
Manfred Focke ◽  
Andrea Feld ◽  
Hartmut K. Lichtenthaler

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.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Regiane Kawasaki ◽  
Rafael A. Baraúna ◽  
Artur Silva ◽  
Marta S. P. Carepo ◽  
Rui Oliveira ◽  
...  

Exiguobacterium antarcticumB7 is extremophile Gram-positive bacteria able to survive in cold environments. A key factor to understanding cold adaptation processes is related to the modification of fatty acids composing the cell membranes of psychrotrophic bacteria. In our study we show thein silicoreconstruction of the fatty acid biosynthesis pathway ofE. antarcticumB7. To build the stoichiometric model, a semiautomatic procedure was applied, which integrates genome information using KEGG and RAST/SEED. Constraint-based methods, namely, Flux Balance Analysis (FBA) and elementary modes (EM), were applied. FBA was implemented in the sense of hexadecenoic acid production maximization. To evaluate the influence of the gene expression in the fluxome analysis, FBA was also calculated using thelog2⁡FCvalues obtained in the transcriptome analysis at 0°C and 37°C. The fatty acid biosynthesis pathway showed a total of 13 elementary flux modes, four of which showed routes for the production of hexadecenoic acid. The reconstructed pathway demonstrated the capacity ofE. antarcticumB7 tode novoproduce fatty acid molecules. Under the influence of the transcriptome, the fluxome was altered, promoting the production of short-chain fatty acids. The calculated models contribute to better understanding of the bacterial adaptation at cold environments.


2020 ◽  
Author(s):  
Michael Burkart ◽  
Thomas Bartholow ◽  
Terra Sztain ◽  
Ashay Patel ◽  
D Lee ◽  
...  

Abstract Fatty acid biosynthesis (FAB) is an essential and highly conserved metabolic pathway. In bacteria, this process is mediated by an elaborate network of protein•protein interactions (PPIs) involving a small, dynamic acyl carrier protein that interacts with dozens of other partner proteins (PPs). These PPIs have remained poorly characterized due to their dynamic and transient nature. Using a combination of solution-phase NMR spectroscopy and protein-protein docking simulations, we report a comprehensive residue-by-residue comparison of the PPIs formed during FAB in Escherichia coli. This work reveals the molecular basis of six discrete binding events responsible for E. coli FAB and offers insights into a method to characterize these events and those in related carrier protein-dependent pathways. ONE SENTENCE SUMMARY: Through a combination of structural and computational analysis, a comparative evaluation of protein-protein interactions in de novo fatty acid biosynthesis in E. coli is performed.


1988 ◽  
Vol 43 (1-2) ◽  
pp. 47-54 ◽  
Author(s):  
Klaus Kobek ◽  
Manfred Focke ◽  
K. Lichtenthaler Botanisches

The effect of the herbicides and aryloxy-phenoxy-propionic acid derivatives diclofop, fenoxaprop, fluazifop and haloxyfop and their ethyl, methyl or butyl esters on the de novo fatty-acid biosynthesis of isolated chloroplasts was investigated with intact chloroplasts isolated from sensitive grasses (Poaceae) and tolerant dicotyledonous plants (Pisum, Spinacia). The 4 herbicides (free-acid form) block the de novo fatty-acid biosynthesis ([2-14C]acetate incorporation into the total fatty-acid fraction) of the sensitive Avena chloroplasts in a dose-dependent manner. The I50- values (a 50% inhibition of the [14C]acetate incorporation) lie in the range of 10-7 to 2 x 10-6 ᴍ. The ethyl or methyl esters (diclofop, fenoxaprop, haloxyfop) and butyl ester (fluazifop) do not affect the de novo fatty-acid biosynthesis of isolated chloroplasts or only at a very high concentration of ca. 10-4 ᴍ. In contrast, the de novo fatty-acid biosynthesis of the tolerant dicotyledonous species (pea, spinach) is not affected by the 4 aryloxy-phenoxy-propionic acid herbicides. In an enzyme preparation isolated from chloroplasts of the herbicide-sensitive barley plants the de novo fatty-acid biosynthesis from [14C]acetate and [14C]acetyl-CoA is blocked by all 4 herbicides (free acids), whereas that of [14C]malonate and [14C]malonyl-CoA is not affected. This strongly suggests that the target of all 4 herbicides (free-acid form) is the acetyl-CoA carboxylase within the chloroplasts. The applied ester derivatives, in turn, which are ineffective in the isolated chloroplast test system, have equally little or no effect on the activity of the acetyl-CoA carboxylase. It is assumed that the acetyl-CoA carboxylase of the tolerant dicot plants investigated is modified in such a way that the 4 herbicides cannot bind to and affect the target


1992 ◽  
Vol 47 (11-12) ◽  
pp. 845-850 ◽  
Author(s):  
Andrea Golz ◽  
Hartmut K. Lichtenthaler

The plant acetyl-CoA synthetase (ACS) is bound to the plastids and provides acetyl-CoA, the starting substrate for de novo fatty acid biosynthesis in plastids. This enzymic reaction, which consumes ATP and releases AMP, can be inhibited by different alkyladenylates such as ethyl-, isopropyl-, propyl- or allyl-adenylates as is shown here. The inhibition mechanism is competitive with respect to ATP and non-com petitive with respect to acetate. I50-values and the inhibition constants K( (ATP), Ki (acetate) and Kii (acetate) are given. The results suggest that, also in plants, acetyl-adenylate is the endogenous intermediate in the enzymic formation of acetyl-CoA from acetate by acetyl-CoA synthetase


1989 ◽  
Vol 44 (7-8) ◽  
pp. 669-672 ◽  
Author(s):  
Klaus Kobek ◽  
Hartmut K. Lichtenthaler

It is demonstrated that - similar to chloroplasts - etioplasts isolated from leaves of pea (Pisumsativum L.) and oat seedlings (Avena sativa L.) also possess a high capacity for de novo fatty acid biosynthesis starting from [1-14C]acetate. The etioplast system proved to be a suitable test system for inhibitors of de novo fatty acid biosynthesis such as cycloxydim , sethoxydim and diclofop. In contrast to the chloroplast test system , the etioplast system is independent of light and also permits screening of photosynthetic herbicides as potential inhibitors of fatty acid biosynthesis.


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