Tags

Type your tag names separated by a space and hit enter

The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of citrate, isocitrate 2-oxoglutarate and malate in flight muscle and isolated mitochondria.
Biochem J. 1975 Mar; 146(3):527-35.BJ

Abstract

1. Blowfly (Phormia regina) flight-muscle mitochondria were allowed to oxidize pyruvate under a variety of experimental conditions, and determinations of the citrate, isocitrate, 2-oxoglutarate and malate contents of both the mitochondria and the incubation medium were made. For each intermediate a substantial portion of the total was present within the mitochondria. 2. Activation of respiration by either ADP or uncoupling agent resulted in a decreased content of citrate and isocitrate and an increased content of 2-oxoglutarate and malate when the substrate was pyruvate, APT and HCO3 minus. Such a decrease in citrate content was obscured when the substrate was pyruvate and proline owing to a large rise in the total content of tricarboxylate-cycle intermediates in the presence of proline and ADP. 3. An experiment involving oligomycin and uncoupling agent demonstrated that the ATP/ADP ratio is the main determinant of flux through the tricarboxylate cycle, with the redox state of nicotinamide nucleotide being of lesser importance. 4. Addition of ADP and Ca-2+ to activate the oxidation of both glycerol 3-phosphate and pyruvate, simulating conditions on initiation of flight, gave a decrease in citrate and isocitrate and an increase in 2-oxoglutarate and malate content. 5. There was a good correlation between these results with isolated flight-muscle mitochondria and the changes found in fly thoraces after 30s and 2 mihorax. 6. It is concluded that NAD-isocitrate dehydrogenase (EC 1.1.1.41) controls the rate of pyruvate oxidation in both resting fly flight muscle in vivo and isolated mitochondria in state 4 (nomenclature of Change & Williams, 1955).

Links

PMC Free PDF

Authors

Johnson RN
No affiliation info available
Hansford RG
No affiliation info available

MeSH

Adenosine DiphosphateAdenosine TriphosphateAnimalsCitratesCitric Acid CycleDipteraGlycerophosphatesIsocitrate DehydrogenaseIsocitratesKetoglutaric AcidsMalatesMitochondria, MuscleMusclesOligomycinsOxidation-ReductionOxygen ConsumptionPyruvatesUncoupling Agents

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1147907

Citation

Johnson, R N., and R G. Hansford. "The Control of Tricarboxylate-cycle Oxidations in Blowfly Flight Muscle. the Steady-state Concentrations of Citrate, Isocitrate 2-oxoglutarate and Malate in Flight Muscle and Isolated Mitochondria." The Biochemical Journal, vol. 146, no. 3, 1975, pp. 527-35.
Johnson RN, Hansford RG. The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of citrate, isocitrate 2-oxoglutarate and malate in flight muscle and isolated mitochondria. Biochem J. 1975;146(3):527-35.
Johnson, R. N., & Hansford, R. G. (1975). The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of citrate, isocitrate 2-oxoglutarate and malate in flight muscle and isolated mitochondria. The Biochemical Journal, 146(3), 527-35.
Johnson RN, Hansford RG. The Control of Tricarboxylate-cycle Oxidations in Blowfly Flight Muscle. the Steady-state Concentrations of Citrate, Isocitrate 2-oxoglutarate and Malate in Flight Muscle and Isolated Mitochondria. Biochem J. 1975;146(3):527-35. PubMed PMID: 1147907.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The control of tricarboxylate-cycle oxidations in blowfly flight muscle. The steady-state concentrations of citrate, isocitrate 2-oxoglutarate and malate in flight muscle and isolated mitochondria. AU - Johnson,R N, AU - Hansford,R G, PY - 1975/3/1/pubmed PY - 1975/3/1/medline PY - 1975/3/1/entrez SP - 527 EP - 35 JF - The Biochemical journal JO - Biochem J VL - 146 IS - 3 N2 - 1. Blowfly (Phormia regina) flight-muscle mitochondria were allowed to oxidize pyruvate under a variety of experimental conditions, and determinations of the citrate, isocitrate, 2-oxoglutarate and malate contents of both the mitochondria and the incubation medium were made. For each intermediate a substantial portion of the total was present within the mitochondria. 2. Activation of respiration by either ADP or uncoupling agent resulted in a decreased content of citrate and isocitrate and an increased content of 2-oxoglutarate and malate when the substrate was pyruvate, APT and HCO3 minus. Such a decrease in citrate content was obscured when the substrate was pyruvate and proline owing to a large rise in the total content of tricarboxylate-cycle intermediates in the presence of proline and ADP. 3. An experiment involving oligomycin and uncoupling agent demonstrated that the ATP/ADP ratio is the main determinant of flux through the tricarboxylate cycle, with the redox state of nicotinamide nucleotide being of lesser importance. 4. Addition of ADP and Ca-2+ to activate the oxidation of both glycerol 3-phosphate and pyruvate, simulating conditions on initiation of flight, gave a decrease in citrate and isocitrate and an increase in 2-oxoglutarate and malate content. 5. There was a good correlation between these results with isolated flight-muscle mitochondria and the changes found in fly thoraces after 30s and 2 mihorax. 6. It is concluded that NAD-isocitrate dehydrogenase (EC 1.1.1.41) controls the rate of pyruvate oxidation in both resting fly flight muscle in vivo and isolated mitochondria in state 4 (nomenclature of Change & Williams, 1955). SN - 0264-6021 UR - https://www.unboundmedicine.com/medline/citation/1147907/The_control_of_tricarboxylate_cycle_oxidations_in_blowfly_flight_muscle__The_steady_state_concentrations_of_citrate_isocitrate_2_oxoglutarate_and_malate_in_flight_muscle_and_isolated_mitochondria_ DB - PRIME DP - Unbound Medicine ER -