Branched-chain Fatty Acid Biosynthesis Research Articles

In vivo and in vitro effects of thiolactomycin on fatty acid biosynthesis in Streptomyces collinus.

A stable-isotope assay was used to analyze the effectiveness of various perdeuterated short-chain acyl coenzyme A (acyl-CoA) compounds as starter units for straight- and branched-chain fatty acid biosynthesis in cell extracts of Streptomyces collinus. In these extracts perdeuterated isobutyryl-CoA was converted to isopalmitate (a branched-chain fatty acid), while butyryl-CoA was converted to palmitate (a straight-chain fatty acid). These observations are consistent with previous in vivo analyses of fatty acid biosynthesis in S. collinus, which suggested that butyryl-CoA and isobutyryl-CoA function as starter units for palmitate and isopalmitate biosynthesis, respectively. Additionally, in vitro analysis demonstrated that acetyl-CoA can function as a starter unit for palmitate biosynthesis. Palmitate biosynthesis and isopalmitate biosynthesis in these cell extracts were both effectively inhibited by thiolactomycin, a known type II fatty acid synthase inhibitor. In vivo experiments demonstrated that concentrations of thiolactomycin ranging from 0.1 to 0.2 mg/ml produced both a dramatic decrease in the cellular levels of branched-chain fatty acids and a surprising three- to fivefold increase in the cellular levels of the straight-chain fatty acids palmitate and myristate. Additional in vivo incorporation studies with perdeuterated butyrate suggested that, in accord with the in vitro studies, the biosynthesis of the palmitate from butyryl-CoA decreases in the presence of thiolactomycin. In contrast, in vivo incorporation studies with perdeuterated acetate demonstrated that the biosynthesis of palmitate from acetyl-CoA increases in the presence of thiolactomycin. These observations clearly demonstrate that isobutyryl-CoA is a starter unit for isopalmitate biosynthesis and that either acetyl-CoA or butyryl-CoA can be a starter unit for palmitate biosynthesis in S. collinus. However, the pathway for palmitate biosynthesis from acetyl-CoA is less sensitive to thiolactomycin, and it is suggested that the basis for this difference is in the initiation step.

分枝鎖脂肪酸の生合成に関する研究

Branched chain fatty acids (BCFAs) of the iso and anteiso series are synthesized from branched-chain amino acids (BCAAs) in many bacteria and in animal skin. This communication describes the biosynthesis of BCFA in Bacillus subtilis and rat skin. BCFAs of Bacillus subtilis are synthesized from the α-keto acids of BCAAs. Two distinct decarboxylases were present in the crude BCFA synthetase of Bacillus subtilis: branched chain α-keto acid (BCKA) decarbaxylase and pyruvate decarboxylase. BCFA synthetase activity was completely lost upon immunoprecipitation of BCKA decarboxylase, suggesting that this enzyme is essential for BCFA biosynthesis by Bacillus subtilis. A BCKA decarboxylase-mediated mechanism was postulated for BCFA biosynthesis. Supplementation of the diet with valine and isoleucine increased the levels of respective BCFAs in the skin surface lipids of rat. However, this was not the case for leucine. Serum levels of valine, isoleucine and their α-keto acids correlated well with the level of the respective BCFAs in the skin surface lipids. Incorporation in vivo of [14C] -BCAA and BCKA into the skin surface lipids revealed that valine and isoleucine rather than their α-keto acids were used mainly for BCFA biosynthesis by rat skin. BCFA synthesis by rat skin differed from that by bacteria in that the systems did not use leucine as a primer. Leucine was used for biosynthesis of straight-chain fatty acids rather than for BCFAs. Substrate specificity and stereoselectivity in vivo of animal BCFA synthesis was described.

Antibacterial Effect of ω-Cyclopentane Fatty Acids Synthesized by Bacillus subtilis 626 from Cyclopentane Carboxylic Acid

Among various cycloalkane carboxylic acids, cyclopentane carboxylic acid was found to be highly active in vivo as a primer molecule of branched-chain fatty acid biosynthesis in Bacillus subtilis 626. The chain-lengthened products derived from this primer substance were identified as ω-cyclopentane undecanoic acid and ω-cyclopentane tridecanoic acid by mass spectrometry. Furthermore, we found that a mixed ethanol solution of fatty acid solutions containing ω-cyclopentane fatty acids, myristic acid and palmitic acid had high antibacterial activity against Bacillus subtilis, and a mixed ethanol solution of palmitic acid and myristic acid had no activity.

In vivo analysis of straight-chain and branched-chain fatty acid biosynthesis in three actinomycetes.

The starter units for branched-chain and straight-chain fatty acid biosynthesis was investigated in vivo in three actinomycetes using stable isotopes. Branched-chain fatty acids, which constitute the majority of the fatty acid pool, were confirmed to be biosynthesized using the amino acid degradation products methylbutyrl-CoA and isobutyrl-CoA as starter units. Straight-chain fatty acids were shown to be constructed using butyrl-CoA as a starter unit. Isomerization of the valine catabolite isobutyryl-CoA was shown to be only a minor source of this butyryl-CoA.

In vivo analysis of straight-chain and branched-chain fatty acid biosynthesis in three actinomycetes

The starter units for branched-chain and straight-chain fatty acid biosynthesis was investigated in vivo in three actinomycetes using stable isotopes. Branched-chain fatty acids, which constitute the majority of the fatty acid pool, were confirmed to be biosynthesized using the amino acid degradation products methylbutyryl-CoA and isobutyryl-CoA as starter units. Straight-chain fatty acids were shown to be constructed using butyryl-CoA as a starter unit. Isomerization of the valine catabolite isobutyryl-CoA was shown to be only a minor source of this butyryl-CoA.

Selective use of L-valine and L-isoleucine for the biosynthesis of branched-chain fatty acids in rat skin.

Iso- and anteiso-fatty acids are detected in more than trace amounts in rat skin surface lipid. The terminal portion of even carbon number iso- and anteiso-fatty acids are synthesized respectively from valine (Val) and isoleucine (Ile) by essentially the same reaction sequences established for straight chain fatty acids. This paper describes the stereospecific biosynthesis of these branched chain fatty acids (BCFAs) and alcohols (BCFALs) in rat skin. Dependence of the concentration of these BCFAs on dietary L-Val and L-Ile was studied. Concentrations of even carbon number iso- and anteiso-fatty acid increased respectively with dietary L-Val and L-Ile. The saturation dose appeared to be 2% for L-Val and 1% for L-Ile. Supplementation of the diet with 2% D-Val, however, did not affect the concentration of even carbon number iso-fatty acid in rat skin surface lipid despite a comparable serum Val level to that of the 2% L-Val group. A similar experiment using 1% DL-Ile found that L-isomer, but not D-isomer, in the circulation was used for the biosynthesis of anteiso-fatty acids. This view was applicable to the incorporation of D-Val and DL-Ile into related BCFALs.

Biosynthesis of branched-chain fatty acids in Bacillus subtilis. A decarboxylase is essential for branched-chain fatty acid synthetase.

Branched long-chain fatty acids of the iso and anteiso series are synthesized in many bacteria from the branched-chain alpha-keto acids of valine, leucine, and isoleucine after their decarboxylation followed by chain elongation. Two distinct branched-chain alpha-keto acid (BCKA) and pyruvate decarboxylases, which are considered to be responsible for primer synthesis, were detected in, and purified in homogenous form from Bacillus subtilis 168 strain by procedures including ammonium sulfate fractionation and chromatography on ion exchange, reversed-phase, and gel absorption columns. The chemical and catalytic properties of the two decarboxylases were studied in detail. The removal of BCKA decarboxylase, using chromatographic fractionation, from the fatty acid synthetase significantly reduced its activity. The synthetase activity was completely lost upon immunoprecipitation of the decarboxylase. The removal of pyruvate decarboxylase by the above two methods, however, did not affect any activity of the fatty acid synthetase. Thus, BCKA decarboxylase, but not pyruvate decarboxylase, is essential for the synthesis of branched-chain fatty acids. The very high affinity of BCKA decarboxylase toward branched-chain alpha-keto acids is responsible for its function in fatty acid synthesis.

Biosynthesis of branched-chain fatty acids from branched-chain amino acids in subcutaneous tissue of the marine little toothed whale, Stenella caeruleo-alba

1. 1. The conversion mechanism for 14CO 2 from [ 14C]Leu, [ 14C]Ile and [ 14C]Val and the incorporation of 14C-amino acids into lipids of subcutaneous tissue (melon and blubber), liver and muscle of the adult whale, Stenella caeruleo-alba were studied using a tissue culture method. 2. 2. Iso-acids such as -5:0, -11:0; -13:0 and -15:0 in melon triglycerides were biosynthesized from [ 14C]Leu. On the other hand, anteiso-acids such as -5:0, -11:0, -13:0, -15:0 and n-11:0 – n-16:0 acids were derived from [ 14C]Ile. 3. 3. Iso-acids such as -4:0, -12:0, -14:0 and 16:0 were biosynthesized from [ 14C]Val. 4. 4. Analytical data indicate that the compositions of these acids biosynthesized were similar to that of fatty acids in whale oil. 5. 5. The branched-chain fatty acid biosynthesized in blubber was iso-5:0 acid from [ 14C]Leu, with no long-chain branched acids, but n-12:0, -14:0 and -16:0 acids were also biosynthesized. 6. 6. Radioactivities derived from 14C-amino acids incorporated into lipids in liver and muscle were extremely low compared with those in subcutaneous tissue. 7. 7. The ratios of 14C-lipids/ 14CO 2 in every 14C-amino acid incorporation were higher in subcutaneous tissue than in liver and muscle, and especially in the case of [ 14C]Leu, the ratio in mclon was quite high. 8. 8. The incorporation of the 14C-amino acids into short- and long-chain acids and alcohols of wax esters was recognized in all experiments.

Biosynthesis of branched-chain fatty acids by preparations from bovine adipose tissue [proceedings

Conference Article| December 01 1978 Biosynthesis of Branched-Chain Fatty Acids by Preparations from Bovine Adipose Tissue KLAUS W. J. WAHLE; KLAUS W. J. WAHLE 1Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar SANDRA M. PATERSON; SANDRA M. PATERSON 1Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar G. ALAN GARTON G. ALAN GARTON 1Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB, Scotland, U.K. Search for other works by this author on: This Site PubMed Google Scholar Biochem Soc Trans (1978) 6 (6): 1157–1158. https://doi.org/10.1042/bst0061157 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation KLAUS W. J. WAHLE, SANDRA M. PATERSON, G. ALAN GARTON; Biosynthesis of Branched-Chain Fatty Acids by Preparations from Bovine Adipose Tissue. Biochem Soc Trans 1 December 1978; 6 (6): 1157–1158. doi: https://doi.org/10.1042/bst0061157 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsBiochemical Society Transactions Search Advanced Search This content is only available as a PDF. © 1978 Biochemical Society1978 Article PDF first page preview Close Modal You do not currently have access to this content.

Biosynthesis of branched long-chain fatty acids from the related short-chain α-keto acid substrates by a cell-free system of Bacillus subtilis

The biosynthesis of branched-chain fatty acids by cell-free extracts of Bacillus subtilis has been studied.The extract of B. subtilis requires α-ketoisovalerate, DPNH, malonyl CoA, TPNH, and dithiothreitol for the synthesis of 14-methylpentadecanoic acid (major acid). Concentrations of α-ketoisovalerate, malonyl CoA, and TPNH giving half maximum activity are 2 μM, 6 μM, and 250 μM, respectively. Relative activity of three α-keto acids, α-ketoisovalerate, α-ketoisocaproate, and L-α-keto-β-methylvalerate for the fatty acid synthesis is in the ratio of 1/2.4/5.3.The B. subtilis extract can be divided into a heat-labile enzyme fraction and a heat-stable fraction, both of which are essential for the synthesis. The enzyme is soluble; all the activity remains in the supernatant when this fraction is treated by ultracentrifugation. The heat-stable factor can be replaced by a similar fraction from an extract of Escherichia coli. The amount in a crude extract of B. subtilis is, however, insufficient to give the full activity to the enzyme fraction.The B. subtilis system incorporates isobutyryl CoA into fatty acids, but not acetyl CoA. The reverse is true of E. coli. Hence the absence of branched-chain acids in E. coli is due both to the lack of α-ketoisovalerate dehydrogenase and to the substrate specificity of the enzyme toward CoA esters.

Fatty Acid-requiring Mutant of Bacillus subtilis Defective in Branched Chain α-Keto Acid Dehydrogenase

A new mutant of Bacillus subtilis is described lacking the activity of branched chain α-keto acid dehydrogenase. The mutant requires short branched chain fatty acids biosynthetically related to leucine, isoleucine, and valine for growth. Long branched chain fatty acids derived from these short molecules can also serve as growth factors. One type of branched chain fatty acid, however, is sufficient to support growth of the mutant at 37°, although wild type cells of B. subtilis normally contain three different pairs of long branched chain fatty acids. Therefore, this mutant allows extensive alterations of the fatty acid composition in membranes of B. subtilis. Straight chain fatty acids do not support growth. Out of a series of tested analogues, 2-methylvalerate, 2-ethyl butyrate, and trimethylacetate were found to be active in vivo as primer molecules of branched chain fatty acid biosynthesis. The chain-lengthened products derived from these primer substrates were characterized by mass spectrometry.

Biosynthesis of branched-chain fatty acids V. Microbial stereospecific syntheses of d-12-methyltetradecanoic and d-14-methylhexadecanoic acids

The fatty acids produced by Bacillus subtilis (ATCC-7059) include the optically active fatty acids, d(+)12-methyltetradecanoic acid, and d(+)14-methylhexadecanoic acid. Tracer experiments have shown that the terminal portion of the anteiso fatty acids are synthesized from pyruvate and α-ketobutyrate (most likely derived from l-threonine) through α-keto-β-methylvalerate by a mechanism similar to that of the synthesis of l-isoleucine de novo. Furthermore, l(+)α-keto-β-methylvalerate, the α-keto acid of l-isoleucine, was incorporated into the terminal-C5 portions with no change in stereoconfiguration at the β-carbon, presumably through the formation of d-α-methylbutyryl CoA. d(−)α-Keto-β-methylvalerate, the α-keto acid of l-alloisoleucine, was incorporated after conversion to its l isomer. d(+)α-Methylbutyrate, stereochemically related to l-isoleucine, was utilized but not its l isomer. In all cases, the d isomer of the anteiso fatty acids was the only product regardless of whether the d or the l isomer of precursor was administered.

The role of isoleucine in the biosynthesis of branched-chain fatty acids by [formula omitted

The role of isoleucine in the biosynthesis of branched-chain fatty acids by [formula omitted