The Tricarboxylic Acid Cycle in Plant Mitochondria: Its Operation and Regulation

Wiskich, Joseph T.; Dry, IB

doi:10.1007/978-3-642-70101-6_11

Cited by 68 publications

(47 citation statements)

References 104 publications

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“…NAD+-dependent ICDH is often considered the rate-limiting step in tricarboxylic acid cycle activity by plant mitochondria (19,24) …”

Section: Discussionmentioning

confidence: 99%

“…Cox and Davies (7) reported that their crude NAD+-ICDH from peas was sigmoidal with respect to isocitrate but that the addition of 1 mm citrate caused the kinetics to change to Michaelis-Menten. Although we could not reproduce this with fresh enzyme, we could show the affect with enzyme that had aged at 40C for 24 h. Under these conditions, the Hill number was 3.1 in the absence of citrate and 1.2 in the 16 18 20 of NAD+, mM- (Table I). The enzyme showed standard Michaelis-Menten kinetics for NAD+ with an apparent Km of 0.2 to 0.8 mm between different enrichment fractions of the enzyme.…”

Section: Enzyme Stability and Purificationmentioning

confidence: 97%

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NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

McIntosh

Oliver²

1992

Plant Physiol.

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The NAD'-dependent isocitrate dehydrogenase from etiolated pea (Pisum sativum L.) mitochondria was purified more than 200-fold by dye-ligand binding on Matrix Gel Blue A and gel filtration on Superose 6. The enzyme was stabilized during purification by the inclusion of 20% glycerol. In crude matrix extracts, the enzyme activity eluted from Superose 6 with apparent molecular masses of 1400 ± 200, 690 ± 90, and 300 ± 50 kD. During subsequent purification steps the larger molecular mass species disappeared and an additional peak at 94 ± 16 kD was evident. The monomer for the enzyme was tentatively identified at 47 kD by sodium dodecyl-polyacrylamide gel electrophoresis. The NADP'-specific isocitrate dehydrogenase activity from mitochondria eluted from Superose 6 at 80 ± 10 kD. About half of the NAD' and NADP'-specific enzymes remained bound to the mitochondrial membranes and was not removed by washing. The NAD -dependent isocitrate dehydrogenase showed sigmoidal kinetics in response to isocitrate (So.s = 0.3 mM). When the enzyme was aged at 4°C or frozen, the isocitrate response showed less allosterism, but this was partially reversed by the addition of citrate to the reaction medium. The NAD+ isocitrate dehydrogenase showed standard Michaelis-Menten kinetics toward NAD+ (Km = 0.2 mM). NADH was a competitive inhibitor (Ki = 0.2 mM) and, unexpectedly, NADPH was a noncompetitive inhibitor (Ki = 0.3 mM). The regulation by NADPH may provide a mechanism for coordination of pyridine nucleotide pools in the mitochondria.

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“…NAD+-dependent ICDH is often considered the rate-limiting step in tricarboxylic acid cycle activity by plant mitochondria (19,24) …”

Section: Discussionmentioning

confidence: 99%

Section: Enzyme Stability and Purificationmentioning

confidence: 97%

NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

McIntosh

Oliver²

1992

Plant Physiol.

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“…However, it is not known whether such increases in respiratory capacity are the cause of increased respiration rates at a set temperature. At moderate growth temperatures, respiration rates in vivo remain well below the maximum capacity of the respiratory system (Wiskich & Dry, 1985). If the same were true after thermal acclimation, changes in capacity would not control the changes in observed respiration rates in vivo.…”

Section:        mentioning

confidence: 96%

“…values at each temperature (b). Wiskich & Dry (1985) found that the activity of isolated mitochondria typically exceeds actual measured rates of intact tissues. Moreover, although glycolytic flux is regulated by the activity of two key enzymes, phosphofructokinase (PFK) and pyruvate kinase (PK), changes in the rate of respiration probably occur primarily via the control of these enzymes by adenylates (i.e.…”

Section:   Q "!     mentioning

confidence: 99%

Response of root respiration to changes in temperature and its relevance to global warming

2000

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Global warming over the next century is likely to be associated with a change in the extent to which atmospheric and soil temperatures fluctuate, on both a daily and a seasonal basis. The average annual temperature of the Earth's surface is expected to increase, as is the frequency of hot days. In this review, we explore what effects short-term and long-term changes in temperature are likely to have on root respiratory metabolism, and what impacts such changes will have on daily, seasonal and annual CO # release by roots under field conditions. We demonstrate that Q "! values, and the degree of acclimation, differ between and within plant species. Changes in the temperature sensitivity of respiration with measuring temperature are highlighted. Temperature-dependent changes in adenylate control and substrate supply are likely to control the Q "! and degree of acclimation of root respiration. Limitations in respiration capacity are unlikely to control respiratory flux at most temperatures. The potential role of nonphosphorylating pathways such as the alternative oxidase in controlling Q "! values is highlighted. The possibility that potentially rapid changes in adenylate control might underlie the acclimation response (rather than slow changes in enzyme capacity) has implications for the total amount of CO # respired by roots daily and annually. Our modelling suggests that rapid acclimation will result in near-perfect homeostasis of respiration rates and minimize annual CO # release. However, annual CO # release increases substantially if the speed of full acclimation is lower. Our modelling exercise also shows that high Q "! values have the potential to increase daily and annual CO # release substantially, particularly if the frequency of hot days increases after global warming.

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“…Enzymes implicated in synthesis and catabolism of this substrate are widely distributed in the cellular compartments. If these enzymes have become well known in herbaceous plants (Macrae, 1971;Davis and Patil, 1975;Wiskich and Dry, 1985;Artus and Edwards, 1985), very few studies have been made on woody plants Cheliak, 1985, 1986;Weimar and Rothe, 1987 (Gerant et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Extraction and study of enzymes linked to malate metabolism in tree leaves

Gérant¹,

Citerne²,

Fabert³

et al. 1989

Ann. For. Sci.

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The Tricarboxylic Acid Cycle in Plant Mitochondria: Its Operation and Regulation

Cited by 68 publications

References 104 publications

NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

Response of root respiration to changes in temperature and its relevance to global warming

Extraction and study of enzymes linked to malate metabolism in tree leaves

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The Tricarboxylic Acid Cycle in Plant Mitochondria: Its Operation and Regulation

Cited by 68 publications

References 104 publications

NAD+-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

NAD+-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

Response of root respiration to changes in temperature and its relevance to global warming

Extraction and study of enzymes linked to malate metabolism in tree leaves

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Product

Resources

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NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria

NAD⁺-Linked Isocitrate Dehydrogenase: Isolation, Purification, and Characterization of the Protein from Pea Mitochondria