scholarly journals A permeability barrier in mitochondria in ‘high-energy states’ against positively charged disulphides

1968 ◽  
Vol 107 (5) ◽  
pp. 645-654 ◽  
Author(s):  
S. Skrede
Keyword(s):  
Oxidative Phosphorylation ◽  
Energy State ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
High Energy ◽  
Rat Liver Mitochondria ◽  
Permeability Barrier ◽  
Inner Mitochondrial Membrane ◽  
Energy States ◽  
State 1

1. In rat liver mitochondria in state 1 or 4 there is a permeability barrier against cystamine, probably in the inner membrane. 2. The permeability barrier was broken (a) when oxidative phosphorylation was uncoupled, (b) when the respiratory chain was inhibited or in anaerobiosis, or (c) when phosphate was added in the absence of exogenous substrate. Under these conditions increased amounts of [35S]cystamine residues were bound to matrix proteins. 3. It appears that the permeability barrier against cystamine in mitochondria reflects a ‘high-energy state’. A gradual increase in the permeability for cystamine strikingly coincided with the loss of respiratory control induced by increasing concentrations of different uncoupling agents. 4. Cystamine caused uncoupling of oxidative phosphorylation in state 2 or 5, but not in state 1, 3 or 4. The uncoupling effect of cystamine was dependent on the phosphorylation potential. ATP counteracted, whereas ADP potentiated, the uncoupling by cystamine. 5. The variable penetration of cystamine appears to depend on its positive charge, since a dication derivative, NNN′N′-tetramethylcystamine, has a similar pattern of penetration, whereas an uncharged derivative, NN′-diacetylcystamine, penetrates rapidly into mitochondria irrespective of their metabolic state. 6. It is suggested that a charge barrier is present in or across the inner mitochondrial membrane in ‘high-energy states’.

scholarly journals The maturation of the inner membrane of foetal rat liver mitochondria. An example of a positive-feedback mechanism

1975 ◽  
Vol 150 (3) ◽  
pp. 477-488 ◽  
Author(s):  
J K Pollak
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Neonatal Rat ◽  
Rat Liver Mitochondria ◽  
Inner Mitochondrial Membrane ◽  
Mature Adult ◽  
Foetal Rat

A new method was devised for the isolation of foetal and neonatal rat lvier mitochondria, giving higher yields than conventional methods. 2. During development from the perinatal period to the mature adult, the ratio of cytochrome oxidase/succinate-cytochrome c reductase changes. 3. The inner mitochondrial membrane of foetal liver mitochondria possesses virtually no osmotic activity; the permeability to sucrose decreases with increasing developmental age. 4. Foetal rat liver mitochondria possess only marginal respiratory control and do not maintain Ca2+-induced respiration; they also swell in respiratory-control medium in the absence of substrate. ATP enhances respiratory control and prevents swelling, adenylyl imidodiphosphate, ATP+atractyloside enhance the R.C.I. (respiratory control index), Ca2+-induced respiratory control and prevent swelling, whereas GTP and low concentrations of ADP have none of these actions. It is concluded that the effect of ATP depends on steric interaction with the inner mitochondrial membrane. 5. When 1-day pre-partum foetuses are obtained by Caesarean section and maintained in a Humidicrib for 90 min, mitochondrial maturation is ‘triggered’, so that their R.C.I. is enhanced and no ATP is required to support Ca2+-dependent respiratory control or to inhibit mitochondrial swelling. 6. It is concluded that foetal rat liver mitochondria in utero do not respire, although they are capable of oxidative phosphorylation in spite of their low R.C.I. The different environmental conditions which the neonatal rat encounters ex utero enable the hepatic mitochondria to produce ATP, which interacts with the inner mitochondrial membrane to enhance oxidative phosphorylation by an autocatalytic mechanism.

scholarly journals Nutritional effects on mitochondrial bioenergetics. Alterations in oxidative phosphorylation by rat liver mitochondria

1984 ◽  
Vol 218 (1) ◽  
pp. 61-67 ◽  
Author(s):  
J Ferreira ◽  
L Gil
Keyword(s):  
Oxidative Phosphorylation ◽  
Respiratory Control ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Atpase ◽  
Protein Free Diet ◽  
Energy Dependent ◽  
Hydrolysis Of ◽  
Rate Controlling Step

Rats malnourished since birth and fed on a protein-free diet for 2 weeks showed a 23-27% decrease in the State-3 oxidation of glutamate, succinate and ascorbate + NNN′ N′-tetramethyl-p-phenylenediamine by liver mitochondria compared with control fed animals. ATP synthesis and the respiratory control index were diminished at the three coupling sites, but significant alterations were not observed in ADP/O ratios. Vmax. for NADH oxidation in electron-transport particles was 40% lower. Mitochondrial cytochromes b and c1 remained unchanged, but cytochrome c was increased by 26%. Cytochromes a + a3 were diminished by 22%. Vmax. for mitochondrial ATPase was 23% lower. These results suggest that the lower content of cytochrome a + a3 at the rate-controlling step of oxidative phosphorylation in malnourished rats might be mainly responsible for the decrease in substrate oxidations as well as ATP synthesis at the three coupling sites. The decreased synthesis and hydrolysis of ATP suggests that other energy-dependent mitochondrial processes could be decreased during malnutrition.

P1, P5-Bis-(5′-adenosyl)pentaphosphate: Is this Adenylate Kinase Inhibitor Substrate for Mitochondrial Processes?

1977 ◽  
Vol 32 (9-10) ◽  
pp. 786-791 ◽  
Author(s):  
Josef Köhrle ◽  
Joachim Lüstorff ◽  
Eckhard Schlimme
Keyword(s):  
Adenylate Kinase ◽  
Kinase Inhibitor ◽  
Adenine Nucleotide ◽  
Nucleoside Diphosphate Kinase ◽  
Liver Mitochondria ◽  
Inhibitory Effect ◽  
Rat Liver Mitochondria ◽  
Intermembrane Space ◽  
Rabbit Muscle ◽  
Inner Mitochondrial Membrane

Abstract 1. P1, P5-Bis-(5′-adenosyl)pentaphosphate (Ap5A) inhibits “soluble” adenylate kinase even when this enzyme is an integral part of the complete mitochondrion. The Ki is 10-5м , i. e. about two orders of magnitude higher than the inhibitor constants determined for the purified adenylate kinase of rabbit muscle and an enzyme preparation separated from the mitochondrial intermembrane space. The weaker inhibitory effect is due to a lower accessibility of the enzyme.2. As to be expected Ap5A which is of the “multisubstrate analogue”-type does not affect mito­ chondrial nucleoside diphosphate kinase.3. Though Ap5A owns the structural elements of both ATP and ADP it is not a substrate of the adenine nucleotide carrier, i.e. neither it is exchanged across the inner mitochondrial membrane nor specifically bound.4. Ap5A is not metabolized by rat liver mitochondria.

scholarly journals Oxidative phosphorylation. The specific binding of trimethyltin and triethyltin to rat liver mitochondria

1970 ◽  
Vol 118 (1) ◽  
pp. 171-179 ◽  
Author(s):  
W. N. Aldridge ◽  
B. W. Street
Keyword(s):  
Adipose Tissue ◽  
Oxidative Phosphorylation ◽  
Brown Adipose Tissue ◽  
Binding Site ◽  
Rat Liver ◽  
Specific Binding ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Affinity Constants ◽  
Brown Adipose

1. The binding of trimethyltin and triethyltin to rat liver mitochondria was determined and the results were analysed by the method of Scatchard (1949). 2. One binding site (site 1) has the correct characteristics for the site to which trimethyltin and triethyltin are attached when they inhibit oxidative phosphorylation. For each compound the concentration of site 1 is 0.8nmol/mg of protein and the ratios of their affinity constants are the same as the ratio of the concentrations inhibiting oxidative phosphorylation. 3. Binding site 1 is present in a fraction derived from mitochondria containing only 15% of the original protein. In this preparation ultrasonication rapidly destroyed site 1. 4. Dimethyltin and diethyltin do not prevent binding of triethyltin to rat liver mitochondria, whereas triethyl-lead does. 5. Trimethyltin and triethyltin bind to mitochondria from brown adipose tissue and the results indicate a binding site 1 similar to that in rat liver mitochondria. 6. The advantages and limitations of this approach to the study of inhibitors are discussed.

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