Adenosine Triphosphatase Activity of Cauliflower Mitochondria

Reid, H. B.; Gentile, Arthur C.; Klein, Reinhild

doi:10.1104/pp.39.6.1020

Cited by 15 publications

(6 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Calcium has been reported to both accelerate (5) and inhibit (14) adenosine triphosphatase. The swelling of cauliflower mitochondria is unaffected or slightlv retarded by 1 mm calcium (11).…”

mentioning

confidence: 99%

Action of Calcium on Corn Mitochondria

1965

View full text Add to dashboard Cite

Our laboratory has been investigating membranelinked functions of plant mitochondria which might help explain active ion transport. Corn mitochondria will actively accumulate calcium + phosphate in a process very like that of animal mitochondria (9); i.e., a high energy intermediate derived from substrate oxidation or ATP furnishes the energy.'With the substrate-powered system, there appears to be a competition between uptake and ATP formation, for the addition of ADP + hexokinase trap diminished calcium uptake. However, unlike animal mitochondria, the corn mitochondria proved to require phosphate for calcium uptake. Furthermore, the accumulation of magniesium and phosphate could not be demonstrated unless some calcium was present.These experiments were done with low concentrations of calcium (0.1-0.2 mm) in order to avoid uncoupling the mitochondria. We had observed that concentrations of calcium of 1 mM and higher reduced P/O ratios, and we assumed that calcium was acting as an uncoupling agent, a view commonly expressed on the basis of experiments with mammalian mitochondria. Calcium has been long known to stimulate acceptorless respiration of animal mitochondria (16,17) and to induce adenosine triphosphatase activity (13), thus mimicking the action of the uncoupling agent, 2,4-dinitrophenol (DNP). Calcium also accelerates the swelling of animal mitochondria, which is thought to reflect a calcium-stimulated release of fatty acids, or U-factor (10).More recent work suggests that the action of calcium is more complex than initially visualized. Chance (2)

show abstract

mentioning

confidence: 99%

Action of Calcium on Corn Mitochondria

1965

View full text Add to dashboard Cite

show abstract

“…Hanson and coworkers have studied these reactions extensively in plant mitochondria (Stoner, Hodges, and Hanson 1964;Hodges and Hanson 1965;Stoner 1965). Millard, Wiskich, and Robertson (1964) presented preliminary work on substrate-powered Mg2+ and Pi accumulation by beet mitochondria, and there are several reports on studies of plant mitochondrial ATPase (Forti 1957;Reid, Gentile, and Klein 1964). Stoner, Hodges, and Hanson (1964), to account for the results in corn shoot mitochondria, have suggested the scheme in Figure 1, which is an extension of schematic relationships drawn up by Slater (1962), Charnock, Rosenthal, and Post (1963), Brierley, Murer, and Buchmann (1964), Connelly and Lardy (1964), and Green et al (1964).…”

Section: Introductionmentioning

confidence: 99%

The Action of 2,4-Dinitrophenol on Corn Root Mitochondria

Bottrill¹,

Hanson²

1969

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

SummaryA study has been made of the action of a wide range of concentrations of 2,4-dinitrophenol (DNP) on the partial reactions of oxidative phosphorylation. DNP at a concentration of 1 X 10-4M caused classic uncoupling of oxidative phosphorylation. Higher concentrations inhibited ,phosphorylation and oxidation. The inhibition of oxidation was due to an inhibition of malate dehydrogenase. The P : ° ratio was reduced by uncoupling and inhibition of the enzymes involved in ATP formation.At a concentration of 1 X 10-3M, DNP has a second peak of stimulation on ATPase activity; mitochondrial swelling was also stimulated but contraction was not affected. Increased swelling at 5 X 1O-3M DNP resulted in disrupted mitochondrial structure and concomitant inhibition of enzyme function, which is shown by an inability of the mitochondria to utilize an energy source to contract, and in an inhibition of ATPase activity.The action of DNP on mitochondria is not a simple enzyme-substrateinhibitor interaction but involves a number of sites in the overall mitochondrial function.

show abstract

“…Inner-membrane spheres have been identified in plant mitochondria, although their identification with the ATPase complex has not been confirmed (20). DNP has been reported to stimulate (27), to inhibit (24), and to have no effect (13,28) on the ATPase associated with plant mitochondria. In addition, pH optima, optimal substrate concentrations, and the requirement for Mg`and K+ ions also have been reported to vary (2,17,24,28).…”

mentioning

confidence: 98%

“…DNP has been reported to stimulate (27), to inhibit (24), and to have no effect (13,28) on the ATPase associated with plant mitochondria. In addition, pH optima, optimal substrate concentrations, and the requirement for Mg`and K+ ions also have been reported to vary (2,17,24,28). To further complicate interpretation of published results, some investigators have not reported respiratory control and ADP/O ratios for their mitochondrial preparations.…”

mentioning

confidence: 99%