Movements of water and ions in mitochondria

Price, Colin; Fonnesu, A; Davies, R. E.

doi:10.1042/bj0640754

Cited by 141 publications

(50 citation statements)

References 24 publications

(38 reference statements)

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“…As the temperature is lowered, the membrane system (plasma membranes, endoplasmic reticulum, mitochondrial membranes) of cells with a higher content of saturated fatty acids would become increasingly rigid in the chilling range (0-100), whereas membranes with more unsaturation in their fatty acids could remain flexible down to 0). A close correlation between oxidative phosphorylation and the swelling and contraction of mitochondria has been described by many workers (7,22).…”

Section: Resultsmentioning

confidence: 99%

Relationship between the Physical Nature of Mitochondrial Membranes and Chilling Sensitivity in Plants

1964

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Section: Resultsmentioning

confidence: 99%

Relationship between the Physical Nature of Mitochondrial Membranes and Chilling Sensitivity in Plants

1964

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“…Enzyme Release At neutral pH ATP maintains mitochondria in a contracted state [34] delaying also the time of onset of mitochondrial swelling [35]. On the other hand, at pH 6.0 and in the presence of phosphate, ATP causes a decrease in the light scattering properties of mitochondria [29].…”

Section: Effect Of Atp On Mitochondria1 Swelling Andmentioning

confidence: 99%

Energy-Dependent Control of the Latency of Mitochondrial Enzymes

et al. 1970

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1.At neutral pH, the temperature-dependent release of glutamate-oxaloacetate aminotransferase, glutamate dehydrogenase, malate dehydrogenase and B-hydroxybutyrate dehydrogenase from mitochondria in an in vitro system, is prevented as a function of the concentration of ATP, oxidizable substrates and ADP. On the other hand, orthophosphate causes the release of mitochondrial enzymes (optimum a t pH 6.5). This effect of Pi is completely inhibited by ADP but not by ATP. UTP and UDP partially replace ADP for this activity. The inhibitory effect of ADP is insensitive to either substrate or rutamycin.2. I n absence of added phosphate and a t acid pH values (optimum at pH 6.0), ATP or oxidizable substrates cause marked release of latent mitochondrial enzymes. ATP shows magnesium requirement for this activity. Inhibitors of electron transport and phosphoryl transfer reactions completely prevent these effects of ATP and substrates. Inhibitors of mitochondrial alkali metal cation uptake are inactive, Rutamycin and dinitrophenol prevent effects of ATP in freshly prepared but not in aged mitochondria.3. Chromatographically pure phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine, but not saturated phospholipids, prevent phosphate from stimulating leakage of latent enzymes from mitochondria.4. Release of mitochondrial enzymes effected by oxidizable substrates, ATP, ADP and orthophosphate, but not phospholipids, seems to be associated with energy-dependent mitochondrial swelling.5. It is concluded that the temperature-dependent release of latent enzymes from mitochondria may depend on structural transformations of the mitochondrial membrane controlled in part by the oxidative phosphorylation mechanism.The limited permeability of the mitochondrial membrane to small anions is one of the main reasons for the apparent unavailability of a number of intramitochondrial enzymes to exogenous substrates. This fact is partly responsible for the phenomenon known as enzyme latency [i]. Recent evidence has suggested that availability of cytoplasmic substrates to latent enzymes in mitochondria may be controlled by: (a) the passive translocation of carboxylic substrate anions associated with energy-dependent uptake of alkali metal cations Permeability properties of mitochondrial membranes responsible for keeping large enzyme molecules within the particle are also important contributors Enzymes.

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“…Additional evidence for the above mentioned interpretations came from observations on changes in low amplitude light scattering and optical density (12-16), which accompanied the "energy states" described by Chance and Williams (17) . Reports (18)(19)(20)(21)(22)(23) appeared previously which showed that energy transduction in the mitochondrion included not only oxidative phosphorylation and active transport but also mechanochemical processes . Other mechanochemical studies have shown that energy derived from ATP (24) or from electron transport (25,26) can drive mitochondrial contraction .…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural Studies of Beef Heart Mitochondria

Weber

1972

The Journal of Cell Biology

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The relationships between membranes and intramembrane compartments of isolated heart mitochondria are inadequately defined to express the induced morphological changes associated with the structural organization. The inner membrane and matrix are the major structural entities which undergo transformation upon alteration of metabolism or incubation conditions. To better express these morphological changes within a mitochondrion, two inner membranes plus enclosed matrix are defined as an inmerix (plural inmerices). Three general morphological forms of mitochondria can be distinguished by the size and shape of inmerices. These are distended, condensed, and coalesced inmerixal configurations. Hypotonic conditions and Pi in isotonic sucrose generate distended configurations. This Pi distention is apparently dependent on utilization of energy. It does not occur under anaerobic conditions. Oxidizable substrates generate condensed configurations. ADP and dADP generate coalesced configurations and stop formation of condensed and distended inmerixal configurations in the absence of inhibitors. ADP coalescence is apparently not dependent on an energy input. It occurs under aerobic and anaerobic conditions, and in isotonic and hypotonic media. Atractyloside completely inhibits the effects of ADP on inmerixal membranes whereas oligomycin does not. Distention by Pi is unaffected by the two inhibitors. Distended inmerices, without added Pi (12 mM and 62 mM sucrose), are coalesced by ADP. These studies indicate that coalescence of inmerixal membranes probably reflects the consequences of specific stoichiometric binding or translocation of adenine nucleotides.

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Movements of water and ions in mitochondria

Cited by 141 publications

References 24 publications

Relationship between the Physical Nature of Mitochondrial Membranes and Chilling Sensitivity in Plants

Relationship between the Physical Nature of Mitochondrial Membranes and Chilling Sensitivity in Plants

Energy-Dependent Control of the Latency of Mitochondrial Enzymes

Ultrastructural Studies of Beef Heart Mitochondria

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