Determination of CO2 Production in Subcellular Preparations Like Synaptosomes and Isolated Mitochondria Using 14C-Labeled Substrates and Radioactive CO2 Measurements

2014 ◽  
pp. 1-24
Author(s):  
Mary C. McKenna ◽  
Irene B. Hopkins
Keyword(s):  
Co2 Production ◽  
Isolated Mitochondria

Measurement of leucine metabolism in man from a primed, continuous infusion of L-[1-3C]leucine

1980 ◽  
Vol 238 (5) ◽  
pp. E473-E479 ◽  
Author(s):  
D. E. Matthews ◽  
K. J. Motil ◽  
D. K. Rohrbaugh ◽  
J. F. Burke ◽  
V. R. Young ◽  
...  
Keyword(s):  
Steady State ◽  
Continuous Infusion ◽  
Co2 Production ◽  
Human Beings ◽  
Priming Dose ◽  
Leucine Metabolism ◽  
Kinetics Of ◽  
13Co2 Enrichment

Leucine metabolism in vivo can be determined from a primed, continuous infusion of L-[1-13C]leucine by measuring, at isotopic steady state, plasm [-13C]leucine enrichment, expired 13CO2 enrichment, and CO2 production rate. With an appropriate priming dose of L-[1-13C]leucine and NaH13CO3, isotopic steady state is reached in less than 2 h, and the infusion is completed in 4 h. The method can determine rates of leucine turnover, oxidation, and incorporation into protein with typical relative uncertainties of 2, 10, and 4%, respectively. The method requires no more than 1 ml of blood and uses stable isotope rather than radioisotope techniques. Thus, the method is applicable to studies of human beings of all ages. L-[1-13C]leucine may be infused with a second amino acid labeled with 15N for simultaneous determination of the kinetics of two amino acids.

Breath water-based doubly labelled water method for the noninvasive determination of CO2 production and energy expenditure in mice

2018 ◽  
Vol 54 (6) ◽  
pp. 561-572 ◽  
Author(s):  
Peter Junghans ◽  
Solvig Görs ◽  
Martina Langhammer ◽  
Cornelia C. Metges
Keyword(s):  
Energy Expenditure ◽  
Co2 Production ◽  
Doubly Labelled Water ◽  
Water Based

scholarly journals Accurate Determination of the Oxidative Phosphorylation Affinity for ADP in Isolated Mitochondria

PLoS ONE ◽  
2011 ◽  
Vol 6 (6) ◽  
pp. e20709 ◽  
Author(s):  
Gilles Gouspillou ◽  
Richard Rouland ◽  
Guillaume Calmettes ◽  
Véronique Deschodt-Arsac ◽  
Jean-Michel Franconi ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Accurate Determination ◽  
Isolated Mitochondria

Real-time determination of CO2 production and estimation of adsorbate coverage on a proton exchange membrane fuel cell under oscillatory operation

2013 ◽  
Vol 17 (7) ◽  
pp. 1851-1859 ◽  
Author(s):  
Pietro P. Lopes ◽  
Bruno C. Batista ◽  
Guilherme A. Saglietti ◽  
Hamilton Varela ◽  
Edson A. Ticianelli
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Co2 Production ◽  
Time Determination ◽  
Exchange Membrane

scholarly journals The pathway of glutamine and glutamate oxidation in isolated mitochondria from mammalian cells

1971 ◽  
Vol 125 (3) ◽  
pp. 757-763 ◽  
Author(s):  
Zoran Kovačević
Keyword(s):  
Glutamate Dehydrogenase ◽  
Mammalian Cells ◽  
Tumour Cells ◽  
Co2 Production ◽  
Isolated Mitochondria ◽  
Ascites Tumour ◽  
Ehrlich Ascites ◽  
Ehrlich Ascites Tumour ◽  
Ascites Tumour Cells ◽  
Ehrlich Ascites Tumour Cells

1. Pyruvate strongly inhibited aspartate production by mitochondria isolated from Ehrlich ascites-tumour cells, and rat kidney and liver respiring in the presence of glutamine or glutamate; the production of14CO2 from l-[U-14C]glutamine was not inhibited though that from l-[U-14C]glutamate was inhibited by more than 50%. 2. Inhibition of aspartate production during glutamine oxidation by intact Ehrlich ascites-tumour cells in the presence of glucose was not accompanied by inhibition of CO2 production. 3. The addition of amino-oxyacetate, which almost completely suppressed aspartate production, did not inhibit the respiration of the mitochondria in the presence of glutamine, though the respiration in the presence of glutamate was inhibited. 4. Glutamate stimulated the respiration of kidney mitochondria in the presence of glutamine, but the production of aspartate was the same as that in the presence of glutamate alone. 5. The results suggest that the oxidation of glutamate produced by the activity of mitochondrial glutaminase can proceed almost completely through the glutamate dehydrogenase pathway if the transamination pathway is inhibited. This indicates that the oxidation of glutamate is not limited by a high [NADPH]/[NADP+] ratio. 6. It is suggested that under physiological conditions the transamination pathway is a less favourable route for the oxidation of glutamate (produced by hydrolysis of glutamine) in Ehrlich ascites-tumour cells, and perhaps also kidney, than the glutamate dehydrogenase pathway, as the production of acetyl-CoA strongly inhibits the first mechanism. The predominance of the transamination pathway in the oxidation of glutamate by isolated mitochondria can be explained by a restricted permeability of the inner mitochondrial membrane to glutamate and by a more favourable location of glutamate–oxaloacetate transaminase compared with that of glutamate dehydrogenase.

Indirect calorimetry with a hood: flow requirements, accuracy, and minute ventilation measurement

1993 ◽  
Vol 74 (1) ◽  
pp. 485-491 ◽  
Author(s):  
B. E. Pennock ◽  
M. Donahoe
Keyword(s):  
Water Vapor ◽  
Indirect Calorimetry ◽  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Co2 Concentration ◽  
Patient Comfort ◽  
Co2 Production ◽  
O2 Concentration ◽  
Expired Gas

Flow-dilution-based hood systems for indirect calorimetry eliminate the conventional mouthpiece or mask of sealed-circuit systems allow measurements with improved patient comfort. This feature is particularly relevant when measurements are made over long periods of time or are repeated often. The flow of air pulled through the hood into the calorimeter in these systems is necessary to clear CO2 from inside the hood. The errors in these systems are greater than those in the sealed-circuit systems and are proportional to the flow. We show that the CO2 concentration within the hood at steady state does not depend on hood size. We describe the accuracy in determination of O2 consumption (VO2), CO2 production, and respiratory exchange ratio with a hood system as a function of the accuracy of the O2 and CO2 analyzers and the water vapor in collected gas. For example, we show that if there is a 1% error in O2 concentration, the percent error in VO2 changes from 5% in a sealed circuit to 51% when a cleansing flow of 50 l/min is introduced. The error in VO2 caused by a 5% error in CO2 determination is 10.6% at this cleansing flow. Removal of 90% of the water vapor (instead of 100%) before analysis of the expired gas introduces a 15.8% error in VO2. By use of the equations described, the accuracy of any measurement system can be determined. In addition, we demonstrate that the measurement of ventilation, usually lost in a hood system, can be preserved using dual pneumotachographs and a sealed hood.

scholarly journals The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of coenzyme A, acetyl-coenzyme A and succinyl-coenzyme A in flight muscle and isolated mitochondria

1974 ◽  
Vol 142 (3) ◽  
pp. 509-519 ◽  
Author(s):  
Richard G. Hansford
Keyword(s):  
Coenzyme A ◽  
Flight Muscle ◽  
Citrate Synthase ◽  
Phormia Regina ◽  
Primary Control ◽  
Glycerol Phosphate ◽  
Acetyl Coa ◽  
Isolated Mitochondria ◽  
Tricarboxylate Cycle

(1) A ‘cycling’ method involving citrate synthase (EC 4.1.3.7) and malate dehydrogenase (EC 1.1.1.37) was modified by the inclusion of succinyl-CoA synthetase (EC 6.2.1.5) and hexokinase (EC 2.7.1.1) to permit the determination of very small amounts of succinyl-CoA in addition to CoA and acetyl-CoA. (2) Application of this technique to blowfly (Phormia regina) flight-muscle extracts reveals no change in acetyl-CoA concentration, a slight fall in CoA concentration and a rise in succinyl-CoA concentration during flight. (3) Extraction of isolated mitochondria during controlled (state 4) pyruvate oxidation reveals essentially only acetyl-CoA. Activation of respiration by ADP (state 3) or uncoupling agents leads to a fall in acetyl-CoA and a rise in CoA and succinyl-CoA content. (4) The presence of glycerol phosphate in addition to pyruvate results in a lower acetyl-CoA content in state 4. (5) It is contended that these results are consistent with a primary control of one of the reactions of the tricarboxylate cycle, rather than of pyruvate dehydrogenase, during the state 4 oxidation of pyruvate by isolated mitochondria, and that the modulation of citrate synthase activity by the ratio of acetyl-CoA/succinyl-CoA is unimportant under these conditions.

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