Oxidative Phosphorylation in Mitochondria

Lardy, Henry A.; Ferguson, Shawn M.

doi:10.1146/annurev.bi.38.070169.005015

Cited by 202 publications

(61 citation statements)

References 134 publications

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“…Our findings suggest that the stoichiometric of the mitochondrial ATPase system observed for isolated F1 preparations by Lardy and co-workers (see 3,181) occurs also in the complete ATPase system and gives rise to the change of the affinity of the adenine nucleotide acceptor site for ATP and ADP. The differences between the effects of oligomycin and aurovertin that have been well discussed by Ernster, Lee and Jan& [5] may be adequately explained by the fact that oligomycin reacts with the F. component of the system [ 181, which appears to control Vmax, whereas aurovertin reacts with the F, component, which ap pears to control the adenine nucledtide affinities.…”

Section: Resultssupporting

confidence: 66%

Influence of aurovertin on affinity of mitochondrial adenosine triphosphatase for ATP and ADP

Mitchell

Moyle

1970

FEBS Letters

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Section: Resultssupporting

confidence: 66%

Influence of aurovertin on affinity of mitochondrial adenosine triphosphatase for ATP and ADP

Mitchell

Moyle

1970

FEBS Letters

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“…and outer mitochondrial membrane (23). If there is an energy source alternative to ATP for respiration-linked ion uptake by plant membranes, it is conceivable that an NADH-oxidizing flavoprotein might be involved.…”

Section: Resultsmentioning

confidence: 99%

Increased Membrane-bound Adenosine Triphosphatase Activity Accompanying Development of Enhanced Solute Uptake in Washed Corn Root Tissue

Leonard

Hanson

1972

Plant Physiol.

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Washing of excised corn (Zea mays L., variety WF9xM14) root tissue is accompanied by an increase in (Mg2+ + K+)-stimulated adenosine triphosphatase. This is the adenosine triphosphatase described by Fisher, Hansen, and Hodges as positively correlated with ion accumulation rates. The increase in activity is confined to the microsomal fraction. A close parallel exists between increases in adenosine triphosphatase and phosphate absorption, and they respond similarly to inhibitors of RNA and protein synthesis. However, the amplitude of change is much smaller in adenosine triphosphatase. Possible reasons for this discrepancy are discussed.In the preceding paper (25) we describe the increase in absorption rates of phosphate, and of some other ions and solutes, which accompanies the washing of roots from seedlings grown under highly aerobic conditions. After an inductive lag period of about 30 min, there is a rapid development of phosphate absorption rate without significant change in respiration rate.Inhibitor studies indicate that RNA and protein synthesis are involved. However, no increase in membranes with washing could be found by electron microscopy or phospholipid analysis. Therefore, "transport" enzymes synthesized must be added to existing membranes. Since the apparent Km values for '2P and '6Rb absorption do not change, it would appear that existing carrier systems must be augmented or activated.One enzymatic system which is being explored for a possible role in ion transport is membrane-bound ATPase (1, 4, 5, 7-10, 12, 15, 17, 22, 29, 33 Incorporation and Distribution of "4C-Leucine. Root segments were incubated in 500-mg lots for 15 min in 10 ml of 0.2 mM CaCi2 containing 0.1 ,uc/ml of uniformly labeled 4C-leucine (316 mc/mmole). After being rinsed for 30 sec in ice-cold water and for 20 min in ice-cold unlabeled 1 mM leucine, the tissue was ground with a conical glass homogenizer in 0.2 M sucrose. The homogenate was successively centrifuged at 2,000g for 10 min (cell wall and nuclei), 12,000g for 20 min (mitochondria), and 80,000g for 60 min.The pellets were washed by resuspension and recentrifugation and were suspended in 0.2 M sucrose. Protein was precipitated from the supernatant, first in 50% saturated (NH4),-SO4 and finally in 8% trichloroacetic acid. Each fraction was washed by resuspension and centrifugation and finally was suspended in 0.2 M sucrose. Aliquots of the pellets, precipitates, and final supernatant were assayed for radioactivity.Protein content was determined colorimetrically (27

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“…2, A and B). Cytochrome c oxidase, a marker for mitochondria (1,17), was coincident with the pH 9.0 ATPase that occurred at a density of 1.18 g/cc (peak I). Of the total membrane-bound cytochrome c oxidase activity in oat roots, 89.5% was in the 13,000g pellet (16).…”

Section: Separation Of Atpase Activities On Continuous Sucrosementioning

confidence: 91%

Membrane-bound Adenosine Triphosphatase Activities of Oat Roots

Leonard¹,

Hansen²,

Hodges³

1973

Plant Physiol.

104

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Homogenates of oat (Arena satira cv. Goodfield) roots contained at least five membrane-associated adenosine triphosphatase (ATPase) activities. The membrane-bound ATPases were separated on sucrose gradients and distinguished by membrane density, pH optima, sensitivity to monovalent salts, and substrate specificity.A membrane fraction sedimenting at low centrifugal force (13,000g) contained two ATPase activities at pH 9.0. One membrane ATPase was coincident with cytochrome c oxidase activity and had a density of 1.18 grams per cubic centimeter. This membrane system was identified as mitochondria. The other pH 9.0 ATPase in this fraction occurred at a density of 1.16 grams per cubic centimeter. The identity of this membrane is unknown.Three additional ATPases were in a membrane fraction sedimenting at high centrifugal forces (13,000-80,000g). One membrane ATPase coincided with NADH-cytochrome c reductase activity, had a density of about 1.09 grams per cubic centimeter, and was equally active at pH 6.0 and 9.0. A second membrane ATPase of the 13,000 to 80,000g fraction had a density of 1.13 grams per cubic centimeter and was more active at pH 9.0 than at pH 6.0. A third membrane ATPase had greater activity at pH 6.0 than at pH 9.0, and the membrane had an apparent density of 1.17 grams per cubic centimeter on the sucrose gradient. This ATPase was especially sensitive to KCI. The identity of the membranes which contain ATPases is discussed in relation to the distribution of other enzymes on the gradient.We have previously described an ATPase from roots that was associated with membranes, required Mg2+, and was stimulated by monovalent salts in general but with KCI and RbCl giving the greatest activation (8). A For the above concept to be tenable, the ATPase must be associated with either the plasma membrane or tonoplast since these membranes are the major sites of active ion transport in higher plants (20,23). Indeed, histochemical studies have shown that both the plasma membrane (11,24) and tonoplast (12,24) have ATPase activities. However, membrane systems of such structures as mitochondria, nuclei, endoplasmic reticulum, and Golgi also possess ATPase activity (12,24). Hence, in vitro assays of ATPase activity employing a crude preparation of membranes (i.e., a differentially centrifuged fraction) may measure several different ATPases. It would be desirable to know how many membrane-associated ATPases can be distinguished in cell extracts and to identify the various membrane systems containing these enzymes. This was the purpose of the investigations reported here. We show that at least five ATPase activities can be distinguished by density gradient centrifugation of membrane fractions from oat roots. One of these ATPases is associated with mitochondria, and another is associated with plasma membranes (16). The latter enzyme is especially sensitive to KCl. The membranes containing the other ATPases are unidentified. MATERIALS AND METHODSPlant Material. Oat seeds (A vena sativa cv. Goodfield) were suspend...

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Oxidative Phosphorylation in Mitochondria

Cited by 202 publications

References 134 publications

Influence of aurovertin on affinity of mitochondrial adenosine triphosphatase for ATP and ADP

Influence of aurovertin on affinity of mitochondrial adenosine triphosphatase for ATP and ADP

Increased Membrane-bound Adenosine Triphosphatase Activity Accompanying Development of Enhanced Solute Uptake in Washed Corn Root Tissue

Membrane-bound Adenosine Triphosphatase Activities of Oat Roots

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