scholarly journals The pyruvate-oxidase system in brain and the tricarboxylic acid cycle*

1949 ◽  
Vol 45 (3) ◽  
pp. 320-325 ◽  
Author(s):  
R. V. Coxon ◽  
C. Liébecq ◽  
R. A. Peters
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Pyruvate Oxidase ◽  
Acid Cycle ◽  
Oxidase System

Studies in the respiratory and carbohydrate metabolism of plant tissues. XII. Further studies of the formation of CO 2 and the changes in lactate, alcohol, sucrose, pyruvate and α -ketoglutarate in potato tubers in nitrogen and in air following anaerobic conditions

1963 ◽  
Vol 157 (968) ◽  
pp. 383-402 ◽  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Sugar Content ◽  
Close Correlation ◽  
Tricarboxylic Acid ◽  
Plant Tissues ◽  
Potato Tubers ◽  
Anaerobic Conditions ◽  
Sweet Potatoes ◽  
Pyruvate Oxidase ◽  
Oxidase System

A specific chromatographic method was used to show that, in air following anaerobiosis, lactate was oxidized to pyruvate and that the latter might be metabolized in the tricarboxylic acid cycle. Our earlier view (Barker & Mapson 1953 b )was thus confirmed. As was expected, both the form and mechanism of the outburst of CO 2 in air after nitrogen were simpler with fully sweet potatoes at 1 °C than with low-sugar potatoes at 10 °C. In the former the outburst of CO 2 appeared to be due only to consumption of lactate; in the latter the outburst of CO 2 was attributed in part to consumption of lactate and in part to change in sugar content. With certain stocks of fully sweet potatoes at 1 °C, the pyruvate oxidase system appeared to be saturated with substrate initially in air after nitrogen; moreover, after 22 days in nitrogen, the pyruvate oxidase system appeared to be almost, if not completely, inhibited. A general, but not a close, correlation was observed between the rates of aerobic respiration and of increase of lactate and output of CO 2 in nitrogen, the rates of these functions being affected by differences in sugar content (Barker 1933) and in metabolic state.

scholarly journals IN VITRO EFFECTS OF FLUORIDE ON TRICARBOXYLIC ACID CYCLE DEHYDROGENASES AND OXIDATIVE PHOSPHORYLATION: PART I

1967 ◽  
Vol 15 (4) ◽  
pp. 195-201 ◽  
Author(s):  
C. JAMES LOVELACE ◽  
GENE W. MILLER
Keyword(s):  
Oxidative Phosphorylation ◽  
Competitive Inhibition ◽  
Tricarboxylic Acid Cycle ◽  
Succinic Dehydrogenase ◽  
Tricarboxylic Acid ◽  
Initial Increase ◽  
Acid Cycle ◽  
Oxidase System ◽  
Vitro Effect

Studies were conducted on the in vitro effect of fluoride on the succinic oxidase system utilizing mitochondria obtained from cauliflower. Preincubation of mitochondria with fluoride did not increase inhibition of succinic oxidase. Various other tricarboxylic acid cycle substrates were used to determine their sensitivity to fluoride; only succinate oxidation was affected. A series of succinate concentrations in the presence and in the absence of fluoride showed increased activity of succinic dehydrogenase, which indicated competitive inhibition. Various concentrations of phosphate in the absence of fluoride showed that phosphate had only slight effects on the succinic 2,6-dichlorophenolindophenol reductase component of the succinic oxidase system. In the absence of phosphate, various concentrations of fluoride showed an initial increase in activity followed by a decrease in activity of succinic 2,6-dichlorophenolindophenol reductase. In the presence of phosphate, fluoride caused marked inhibition of succinic 2,6-dichlorophenolindophenol reductase. It is believed that this inhibition results from an enzyme-fluorophosphate complex which has a lower dissociation constant than that of the enzyme-substrate complex. An oxidative phosphorylation study indicated that both respiration and phosphorylation were inhibited.

AN ANOMALOUS TRICARBOXYLIC ACID CYCLE IN ACETOBACTER MELANOGENUM

1960 ◽  
Vol 38 (3) ◽  
pp. 193-203 ◽  
Author(s):  
D. H. Bone ◽  
R. M. Hochster
Keyword(s):  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Oxidase System ◽  
Isocitric Dehydrogenase ◽  
Highly Active ◽  
Carbon Compounds ◽  
Condensing Enzyme

Extracts of gluconate-grown Acetobacter melanogenum contain condensing enzyme and DPN-isocitric dehydrogenase of low specific activity. No evidence could be found for the presence of phosphotransacetylase, aconitase, or TPN-isocitric dehydrogenase. Since the organism or its extracts cannot synthesize the necessary four carbon compounds from pyruvate and from acetate, it is concluded that the tricarboxylic acid cycle does not function in extracts of this organism in the usually accepted manner.The pyruvic oxidase system was found to be highly active, acetaldehyde being the chief intermediate and acetate the end product. The mechanism for the slow incorporation of acetate into other cell constituents is, at present, unknown.

AN ANOMALOUS TRICARBOXYLIC ACID CYCLE IN ACETOBACTER MELANOGENUM

1960 ◽  
Vol 38 (1) ◽  
pp. 193-203 ◽  
Author(s):  
D. H. Bone ◽  
R. M. Hochster
Keyword(s):  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Oxidase System ◽  
Isocitric Dehydrogenase ◽  
Highly Active ◽  
Carbon Compounds ◽  
Condensing Enzyme

Extracts of gluconate-grown Acetobacter melanogenum contain condensing enzyme and DPN-isocitric dehydrogenase of low specific activity. No evidence could be found for the presence of phosphotransacetylase, aconitase, or TPN-isocitric dehydrogenase. Since the organism or its extracts cannot synthesize the necessary four carbon compounds from pyruvate and from acetate, it is concluded that the tricarboxylic acid cycle does not function in extracts of this organism in the usually accepted manner.The pyruvic oxidase system was found to be highly active, acetaldehyde being the chief intermediate and acetate the end product. The mechanism for the slow incorporation of acetate into other cell constituents is, at present, unknown.

scholarly journals Effects of sevoflurane anesthesia and abdominal surgery on the systemic metabolome: a prospective observational study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yiyong Wei ◽  
Donghang Zhang ◽  
Jin Liu ◽  
Mengchan Ou ◽  
Peng Liang ◽  
...  
Keyword(s):  
Abdominal Surgery ◽  
General Anesthesia ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Metabolic Changes ◽  
Sevoflurane Anesthesia ◽  
Glutamate Metabolism ◽  
Acid Cycle ◽  
Link Type ◽  
The Mean

Abstract Background Metabolic status can be impacted by general anesthesia and surgery. However, the exact effects of general anesthesia and surgery on systemic metabolome remain unclear, which might contribute to postoperative outcomes. Methods Five hundred patients who underwent abdominal surgery were included. General anesthesia was mainly maintained with sevoflurane. The end-tidal sevoflurane concentration (ETsevo) was adjusted to maintain BIS (Bispectral index) value between 40 and 60. The mean ETsevo from 20 min after endotracheal intubation to 2 h after the beginning of surgery was calculated for each patient. The patients were further divided into low ETsevo group (mean − SD) and high ETsevo group (mean + SD) to investigate the possible metabolic changes relevant to the amount of sevoflurane exposure. Results The mean ETsevo of the 500 patients was 1.60% ± 0.34%. Patients with low ETsevo (n = 55) and high ETsevo (n = 59) were selected for metabolomic analysis (1.06% ± 0.13% vs. 2.17% ± 0.16%, P < 0.001). Sevoflurane and abdominal surgery disturbed the tricarboxylic acid cycle as identified by increased citrate and cis-aconitate levels and impacted glycometabolism as identified by increased sucrose and D-glucose levels in these 114 patients. Glutamate metabolism was also impacted by sevoflurane and abdominal surgery in all the patients. In the patients with high ETsevo, levels of L-glutamine, pyroglutamic acid, sphinganine and L-selenocysteine after sevoflurane anesthesia and abdominal surgery were significantly higher than those of the patients with low ETsevo, suggesting that these metabolic changes might be relevant to the amount of sevoflurane exposure. Conclusions Sevoflurane anesthesia and abdominal surgery can impact principal metabolic pathways in clinical patients including tricarboxylic acid cycle, glycometabolism and glutamate metabolism. This study may provide a resource data for future studies about metabolism relevant to general anaesthesia and surgeries. Trial registration www.chictr.org.cn. identifier: ChiCTR1800014327.

scholarly journals Triheptanoin partially restores levels of tricarboxylic acid cycle intermediates in the mouse pilocarpine model of epilepsy

2013 ◽  
Vol 129 (1) ◽  
pp. 107-119 ◽  
Author(s):  
Mussie G. Hadera ◽  
Olav B. Smeland ◽  
Tanya S. McDonald ◽  
Kah Ni Tan ◽  
Ursula Sonnewald ◽  
...  
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Pilocarpine Model ◽  
Tricarboxylic Acid Cycle Intermediates
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