scholarly journals ATP Synthesis-coupled and -uncoupled Acetate Production from Acetyl-CoA by Mitochondrial Acetate:Succinate CoA-transferase and Acetyl-CoA Thioesterase inTrypanosoma

2012 ◽  
Vol 287 (21) ◽  
pp. 17186-17197 ◽  
Author(s):  
Yoann Millerioux ◽  
Pauline Morand ◽  
Marc Biran ◽  
Muriel Mazet ◽  
Patrick Moreau ◽  
...  
Keyword(s):  
Atp Synthesis ◽  
Acetate Production ◽  
Acetyl Coa ◽  
Coa Transferase

scholarly journals Acetate:Succinate CoA-transferase in the Hydrogenosomes of Trichomonas vaginalis

2007 ◽  
Vol 283 (3) ◽  
pp. 1411-1418 ◽  
Author(s):  
Koen W. A. van Grinsven ◽  
Silke Rosnowsky ◽  
Susanne W. H. van Weelden ◽  
Simone Pütz ◽  
Mark van der Giezen ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Enzymatic Reaction ◽  
Protozoan Parasite ◽  
Transferase Activity ◽  
Acetate Production ◽  
Acetyl Coa ◽  
Gene Encoding ◽  
Homologous Overexpression ◽  
Coa Transferase ◽  
Coa Hydrolase

Acetate:succinate CoA-transferases (ASCT) are acetate-producing enzymes in hydrogenosomes, anaerobically functioning mitochondria and in the aerobically functioning mitochondria of trypanosomatids. Although acetate is produced in the hydrogenosomes of a number of anaerobic microbial eukaryotes such as Trichomonas vaginalis, no acetate producing enzyme has ever been identified in these organelles. Acetate production is the last unidentified enzymatic reaction of hydrogenosomal carbohydrate metabolism. We identified a gene encoding an enzyme for acetate production in the genome of the hydrogenosome-containing protozoan parasite T. vaginalis. This gene shows high similarity to Saccharomyces cerevisiae acetyl-CoA hydrolase and Clostridium kluyveri succinyl-CoA:CoA-transferase. Here we demonstrate that this protein is expressed and is present in the hydrogenosomes where it functions as the T. vaginalis acetate:succinate CoA-transferase (TvASCT). Heterologous expression of TvASCT in CHO cells resulted in the expression of an active ASCT. Furthermore, homologous overexpression of the TvASCT gene in T. vaginalis resulted in an equivalent increase in ASCT activity. It was shown that the CoA transferase activity is succinate-dependent. These results demonstrate that this acetyl-CoA hydrolase/transferase homolog functions as the hydrogenosomal ASCT of T. vaginalis. This is the first hydrogenosomal acetate-producing enzyme to be identified. Interestingly, TvASCT does not share any similarity with the mitochondrial ASCT from Trypanosoma brucei, the only other eukaryotic succinate-dependent acetyl-CoA-transferase identified so far. The trichomonad enzyme clearly belongs to a distinct class of acetate:succinate CoA-transferases. Apparently, two completely different enzymes for succinate-dependent acetate production have evolved independently in ATP-generating organelles.

Acetyl-CoA synthetase (ADP forming) in archaea, a novel enzyme involved in acetate formation and ATP synthesis

1993 ◽  
Vol 159 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Thomas Sch�fer ◽  
Martina Selig ◽  
Peter Sch�nheit
Keyword(s):  
Atp Synthesis ◽  
Acetyl Coa ◽  
Acetate Formation

scholarly journals Degradation of Glyoxylate and Glycolate with ATP Synthesis by a Thermophilic Anaerobic Bacterium, Moorella sp. Strain HUC22-1

2007 ◽  
Vol 74 (5) ◽  
pp. 1447-1452 ◽  
Author(s):  
Shinsuke Sakai ◽  
Kentaro Inokuma ◽  
Yutaka Nakashimada ◽  
Naomichi Nishio
Keyword(s):  
Batch Culture ◽  
Yeast Extract ◽  
Anaerobic Bacterium ◽  
Atp Synthesis ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Enzyme Reactions ◽  
Substrate Level ◽  
Key Enzyme ◽  
Atp Generation

ABSTRACT The thermophilic homoacetogenic bacterium Moorella sp. strain HUC22-1 ferments glyoxylate to acetate roughly according to the reaction 2 glyoxylate → acetate + 2 CO2. A batch culture with glyoxylate and yeast extract yielded 11.7 g per mol of cells per substrate, which was much higher than that obtained with H2 plus CO2. Crude extracts of glyoxylate-grown cells catalyzed the ADP- and NADP-dependent condensation of glyoxylate and acetyl coenzyme A (acetyl-CoA) to pyruvate and CO2 and converted pyruvate to acetyl-CoA and CO2, which are the key reactions of the malyl-CoA pathway. ATP generation was also detected during the key enzyme reactions of this pathway. Furthermore, this bacterium consumed l-malate, an intermediate in the malyl-CoA pathway, and produced acetate. These findings suggest that Moorella sp. strain HUC22-1 can generate ATP by substrate-level phosphorylation during glyoxylate catabolism through the malyl-CoA pathway.

scholarly journals Properties of Succinyl-Coenzyme A:l-Malate Coenzyme A Transferase and Its Role in the Autotrophic 3-Hydroxypropionate Cycle of Chloroflexus aurantiacus

2006 ◽  
Vol 188 (7) ◽  
pp. 2646-2655 ◽  
Author(s):  
Silke Friedmann ◽  
Astrid Steindorf ◽  
Birgit E. Alber ◽  
Georg Fuchs
Keyword(s):  
Escherichia Coli ◽  
Coenzyme A ◽  
Chloroflexus Aurantiacus ◽  
Class Iii ◽  
Terminal Amino Acid ◽  
Acetyl Coa ◽  
Acetyl Coenzyme A ◽  
Coa Transferase ◽  
Terminal Amino ◽  
Terminal Amino Acid Sequence

ABSTRACT The 3-hydroxypropionate cycle has been proposed to operate as the autotrophic CO2 fixation pathway in the phototrophic bacterium Chloroflexus aurantiacus. In this pathway, acetyl coenzyme A (acetyl-CoA) and two bicarbonate molecules are converted to malate. Acetyl-CoA is regenerated from malyl-CoA by l-malyl-CoA lyase. The enzyme forming malyl-CoA, succinyl-CoA:l-malate coenzyme A transferase, was purified. Based on the N-terminal amino acid sequence of its two subunits, the corresponding genes were identified on a gene cluster which also contains the gene for l-malyl-CoA lyase, the subsequent enzyme in the pathway. Both enzymes were severalfold up-regulated under autotrophic conditions, which is in line with their proposed function in CO2 fixation. The two CoA transferase genes were cloned and heterologously expressed in Escherichia coli, and the recombinant enzyme was purified and studied. Succinyl-CoA:l-malate CoA transferase forms a large (αβ)n complex consisting of 46- and 44-kDa subunits and catalyzes the reversible reaction succinyl-CoA + l-malate → succinate + l-malyl-CoA. It is specific for succinyl-CoA as the CoA donor but accepts l-citramalate instead of l-malate as the CoA acceptor; the corresponding d-stereoisomers are not accepted. The enzyme is a member of the class III of the CoA transferase family. The demonstration of the missing CoA transferase closes the last gap in the proposed 3-hydroxypropionate cycle.

scholarly journals Signaling in TRPV1-induced platelet activating factor (PAF) in human esophageal epithelial cells

2010 ◽  
Vol 298 (2) ◽  
pp. G233-G240 ◽  
Author(s):  
Jie Ma ◽  
Karen M. Harnett ◽  
Jose Behar ◽  
Piero Biancani ◽  
Weibiao Cao
Keyword(s):  
Epithelial Cells ◽  
Western Blot ◽  
Transient Receptor Potential ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Transferase Activity ◽  
Ionophore A23187 ◽  
Acetyl Coa ◽  
Coa Transferase

Transient receptor potential channel, vanilloid subfamily member 1 (TRPV1) receptors were identified in human esophageal squamous epithelial cell line HET-1A by RT-PCR and by Western blot. In fura-2 AM-loaded cells, the TRPV1 agonist capsaicin caused a fourfold cytosolic calcium increase, supporting a role of TRPV1 as a capsaicin-activated cation channel. Capsaicin increased production of platelet activating factor (PAF), an important inflammatory mediator that acts as a chemoattractant and activator of immune cells. The increase was reduced by the p38 MAP kinase (p38) inhibitor SB203580, by the cytosolic phospholipase A2 (cPLA2) inhibitor AACOCF3, and by the lyso-PAF acetyltransferase inhibitor sanguinarin, indicating that capsaicin-induced PAF production may be mediated by activation of cPLA2, p38, and lyso-PAF acetyltransferase. To establish a sequential signaling pathway, we examined the phosphorylation of p38 and cPLA2 by Western blot. Capsaicin induced phosphorylation of p38 and cPLA2. Capsaicin-induced p38 phosphorylation was not affected by AACOCF3. Conversely, capsaicin-induced cPLA2 phosphorylation was blocked by SB203580, indicating that capsaicin-induced PAF production depends on sequential activation of p38 and cPLA2. To investigate how p38 phosphorylation may result from TRPV1-mediated calcium influx, we examined a possible role of calmodulin kinase (CaM-K). p38 phosphorylation was stimulated by the calcium ionophore A23187 and by capsaicin, and the response to both agonists was reduced by a CaM inhibitor and by CaM-KII inhibitors, indicating that calcium induced activation of CaM and CaM-KII results in P38 phosphorylation. Acetyl-CoA transferase activity increased in response to capsaicin and was inhibited by SB203580, indicating that p38 phosphorylation in turn causes activation of acetyl-CoA transferase to produce PAF. Thus epithelial cells produce PAF in response to TRPV1-mediated calcium elevation.

scholarly journals Autotrophic CO2 Fixation by Chloroflexus aurantiacus: Study of Glyoxylate Formation and Assimilation via the 3-Hydroxypropionate Cycle

2001 ◽  
Vol 183 (14) ◽  
pp. 4305-4316 ◽  
Author(s):  
Sylvia Herter ◽  
Jan Farfsing ◽  
Nasser Gad'On ◽  
Christoph Rieder ◽  
Wolfgang Eisenreich ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Calvin Cycle ◽  
Carbon Assimilation ◽  
Growth Conditions ◽  
Chloroflexus Aurantiacus ◽  
Acetyl Coa ◽  
Autotrophic Co2 Fixation ◽  
Whole Cells ◽  
Coa Transferase ◽  
Malonyl Coa

ABSTRACT In the facultative autotrophic organism Chloroflexus aurantiacus, a phototrophic green nonsulfur bacterium, the Calvin cycle does not appear to be operative in autotrophic carbon assimilation. An alternative cyclic pathway, the 3-hydroxypropionate cycle, has been proposed. In this pathway, acetyl coenzyme A (acetyl-CoA) is assumed to be converted to malate, and two CO2 molecules are thereby fixed. Malyl-CoA is supposed to be cleaved to acetyl-CoA, the starting molecule, and glyoxylate, the carbon fixation product. Malyl-CoA cleavage is shown here to be catalyzed by malyl-CoA lyase; this enzyme activity is induced severalfold in autotrophically grown cells. Malate is converted to malyl-CoA via an inducible CoA transferase with succinyl-CoA as a CoA donor. Some enzyme activities involved in the conversion of malonyl-CoA via 3-hydroxypropionate to propionyl-CoA are also induced under autotrophic growth conditions. So far, no clue as to the first step in glyoxylate assimilation has been obtained. One possibility for the assimilation of glyoxylate involves the conversion of glyoxylate to glycine and the subsequent assimilation of glycine. However, such a pathway does not occur, as shown by labeling of whole cells with [1,2-13C2]glycine. Glycine carbon was incorporated only into glycine, serine, and compounds that contained C1 units derived therefrom and not into other cell compounds.

scholarly journals Measurement of the rates of acetyl-CoA hydrolysis and synthesis from acetate in rat hepatocytes and the role of these fluxes in substrate cycling

1990 ◽  
Vol 270 (1) ◽  
pp. 219-225 ◽  
Author(s):  
B Crabtree ◽  
M J Gordon ◽  
S L Christie
Keyword(s):  
Heat Production ◽  
Rat Hepatocytes ◽  
Total Heat ◽  
Acetate Production ◽  
Acetyl Coa ◽  
Acetyl Coa Synthesis ◽  
Acetate Utilization ◽  
Net Flux

1. Acetyl-CoA hydrolysis, acetyl-CoA synthesis from acetate and several related fluxes were measured in rat hepatocytes. 2. In contrast with acetyl-CoA hydrolysis, most of the acetyl-CoA synthesis from acetate occurred in the mitochondria. 3. Acetyl-CoA hydrolysis was not significantly affected by 24 h starvation or (-)-hydroxycitrate. 4. In the cytoplasm there was a net flux of acetyl-CoA to acetate, and substrate cycling between acetate and acetyl-CoA in this compartment was very low, accounting for less than 0.1% of the total heat production by the animal. 5. A larger cycle, involving mitochondrial and cytoplasmic acetate and acetyl-CoA, may operate in fed animals, but would account for only approx 1% of total heat production. 6. It is proposed that the opposing fluxes of mitochondrial acetate utilization and cytoplasmic net acetate production may provide sensitivity, feedback and buffering, even when these fluxes are not linked to form a conventional substrate cycle.

scholarly journals A new pathway for forming acetate and synthesizing ATP during fermentation in bacteria

2020 ◽  
Author(s):  
Bo Zhang ◽  
Courtney Bowman ◽  
Timothy J. Hackmann
Keyword(s):  
High Energy ◽  
Acetate Kinase ◽  
Acetyl Phosphate ◽  
Biochemical Pathway ◽  
Common Pathway ◽  
Acetyl Coa ◽  
Enzymatic Assays ◽  
Biochemical Pathways ◽  
Coa Transferase ◽  
Fermentative Bacteria

ABSTRACTMany bacteria and other organisms form acetate during fermentation. Forming acetate from high energy-precursors (acetyl-CoA or acetyl phosphate) is one of the few ways that fermentative bacteria generate ATP. Here we found a biochemical pathway for forming acetate and synthesizing ATP that was unknown in bacteria. We found the bacterium Cutibacterium granulosum formed acetate during fermentation of glucose. With enzymatic assays, we showed it formed acetate using a pathway involving two enzymes. The first enzyme, succinyl-CoA:acetate CoA-transferase (SCACT), forms acetate from acetyl-CoA. The second enzyme, succinyl-CoA synthetase (SCS), synthesizes ATP. This pathway is common in eukaryotes, but it has not been found in bacteria or other organisms. We found two related bacteria (C. acnes and Acidipropionibacterium acidipropionici) also used this pathway. None used the most common pathway for forming acetate in bacteria (involving acetate kinase and phosphotransacetylase). The SCACT/SCS pathway may be used by many bacteria, not just C. granulosum and relatives. When we searched genomes for bacteria known to form acetate, we found over 1/6 encoded this pathway. These bacteria belong to 104 different species and subspecies in 12 different phyla. With this discovery, all five pathways known to form acetate and ATP during fermentation can be found in bacteria. This discovery is important to manipulating fermentation and to the evolution of biochemical pathways.

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