scholarly journals Studies of intermediary metabolism in germinating pea cotyledons. The pathway of ethanol metabolism and the role of the tricarboxylic acid cycle

1967 ◽  
Vol 105 (1) ◽  
pp. 323-331 ◽  
Author(s):  
D. S. Cameron ◽  
E. A. Cossins
Keyword(s):  
Carbon Dioxide ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Ethanol Metabolism ◽  
Similar Data ◽  
Tissue Slices ◽  
Acid Cycle ◽  
Pea Seedlings ◽  
Fixation Of Carbon Dioxide

1. The pathway of ethanol metabolism in cotyledons of 3-day-old pea seedlings has been examined by incubating tissue slices with [1−14C]ethanol and [2−14C]ethanol for periods up to 1hr. 2. Ethanol was rapidly incorporated into citrate and glutamate but relatively small amounts of 14C were present in the evolved carbon dioxide even after 1hr. of ethanol metabolism. 3. Similar data were obtained from experiments in which [1,2−14C2]acetaldehyde and [14C]acetate were supplied. 4. The results are interpreted as indicating that ethanol is metabolized essentially via the reactions of the tricarboxylic acid cycle with a substantial drain of α-oxoglutarate to support the biosynthesis of glutamate. 5. It is concluded that oxaloacetate, required for the incorporation of ethanol into citrate, arises mainly from the transamination of aspartate and the fixation of carbon dioxide.

Address of the President Sir Howard Florey, at the Anniversary Meeting, 30 November 1961

1961 ◽  
Vol 265 (1320) ◽  
pp. 1-14 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acids ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Biological Degradation ◽  
Tissue Slices ◽  
Carbamyl Phosphate ◽  
Acid Cycle ◽  
Main Route ◽  
Carbon Fragment

Award of Medals 1961 The Copley Medal is awarded to Sir Hans Krebs, F.R.S. Sir Hans Krebs has made outstanding contributions to knowledge of the chemical pathways of metabolism. In 1932, with Henseleit, he used tissue slices to demonstrate the synthesis of urea and found that additions of ornithine stimulated the process. Ornithine was regarded as uniting with carbon dioxide and ammonia to give arginine, with citrulline as an intermediate. The enzyme arginase liberated urea and a molecule of ornithine, so that the process could begin again. Subsequent research has shown that the postulated cycle is essentially valid, although more detail has been introduced; carbamyl phosphate, argininosuccinate and adenosine triphosphate have been brought in and aspartic acid has replaced ammonia in the reaction with citrulline. The more complicated version owes much to the fundamental work initiated by Krebs in 1937 on the tricarboxylic acid cycle. This process is now seen as the main route for oxidizing the two-carbon fragment produced in the biological degradation of carbohydrates, fatty acids and arninoacids.

scholarly journals Studies of the Fixation of Carbon Dioxide by Washed Ram Spermatozoa

1970 ◽  
Vol 23 (4) ◽  
pp. 889 ◽  
Author(s):  
T O'shea ◽  
RG Wales
Keyword(s):  
Carbon Dioxide ◽  
Substrate Concentration ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Tricarboxylic Acid Cycle Intermediates ◽  
Fixation Of Carbon Dioxide

Fixation of carbon dioxide by ram spermatozoa was studied by incubating washed cells with NaH14C03? More fixation of carbon dioxide occurred as the substrate concentration was increased, and was very low in the absence of added substrate. Less incorporation occurred with acetate than with pyruvate or lactate. A marked increase in fixation was seen when ketoglutarate or malate replaced portion of the lactate in the medium, but not when other tricarboxylic acid cycle intermediates were substituted. Fixation of carbon dioxide was higher when ketoglutarate plus malate rather than when either substrate alone partially replaced lactate.

scholarly journals Enhancing Bioethanol Production by Deleting Phosphoenolpyruvate Synthase and ADP-Glucose Pyrophosphorylase, and Shunting Tricarboxylic Acid Cycle In Synechocystis Sp. PCC 6803

2021 ◽  
Author(s):  
E-Bin Gao ◽  
Penglin Ye ◽  
Haiyan Qiu ◽  
Junhua Wu ◽  
Huayou Chen
Keyword(s):  
Carbon Dioxide ◽  
Ethanol Production ◽  
Atmospheric Carbon Dioxide ◽  
Metabolic Flux ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Photosynthetic Production ◽  
Engineered Strain ◽  
Pcc 6803

Abstract Background: The outstanding ability of directly assimilating carbon dioxide and sunlight to produce biofuels and chemicals impels photosynthetic cyanobacteria to become attractive organisms for the solution to the global warming crises and the world energy growth. The cyanobacteria-based method for ethanol production has been increasingly regarded as alternatives to food biomass-based fermentation and traditional petroleum-based production. Therefore, we engineered the model cyanobacterium Synechocystis sp. PCC 6803 to synthesize ethanol and optimized the biosynthetic pathways for improving ethanol production under photoautotrophic conditions.Results: In this study, we successfully achieved the photosynthetic production of ethanol from atmospheric carbon dioxide by an engineered mutant Synechocystis sp. PCC 6803 with over-expressing the heterologous genes encoding Zymomonas mobilis pyruvate decarboxylase (PDC) and Escherichia coli NADPH-dependent alcohol dehydrogenase (YqhD). The engineered strain was further optimized by an alternative engineering approach to improve cell growth, and increase the intracellular supply of the precursor pyruvate for ethanol production under photoautotrophic conditions. This approach includes blocking phosphoenolpyruvate synthetic pathway from pyruvate, removing glycogen storage, and shunting carbon metabolic flux of tricarboxylic acid cycle. Through redirecting and optimizing the metabolic carbon flux of Synechocystis, a high ethanol-producing efficiency was achieved (248 mg L-1 day-1) under photoautotrophic conditions with atmospheric CO2 as the sole carbon source. Conclusions: The engineered strain SYN009 (∆slr0301/pdc-yqhD, ∆slr1176/maeB) would become a valuable biosystem for photosynthetic production of ethanol and for expanding our knowledge of exploiting cyanobacteria to produce value chemicals directly from atmospheric CO2.

Sporulation ofGibberella ZeaeIV. Role of the Tricarboxylic-Acid Cycle in Macroconidium Production

Mycologia ◽  
1979 ◽  
Vol 71 (4) ◽  
pp. 688-698 ◽  
Author(s):  
Bor-Fuei Huang ◽  
R. F. Dawson ◽  
R. A. Cappellini
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle

scholarly journals Role of Phosphoenolpyruvate in the NADP-Isocitrate Dehydrogenase and Isocitrate Lyase Reaction in Escherichia coli

2006 ◽  
Vol 189 (3) ◽  
pp. 1176-1178 ◽  
Author(s):  
Tadashi Ogawa ◽  
Keiko Murakami ◽  
Hirotada Mori ◽  
Nobuyoshi Ishii ◽  
Masaru Tomita ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Isocitrate Dehydrogenase ◽  
Isocitrate Lyase ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Glyoxylate Shunt ◽  
Acid Cycle ◽  
Uncompetitive Inhibition

ABSTRACT Phosphoenolpyruvate inhibited Escherichia coli NADP-isocitrate dehydrogenase allosterically (Ki of 0.31 mM) and isocitrate lyase uncompetitively (Ki ′ of 0.893 mM). Phosphoenolpyruvate enhances the uncompetitive inhibition of isocitrate lyase by increasing isocitrate, which protects isocitrate dehydrogenase from the inhibition, and contributes to the control through the tricarboxylic acid cycle and glyoxylate shunt.

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