THE UPTAKE OF GLYCINE BY RAT BRAIN MITOCHONDRIA

1965 ◽  
Vol 43 (7) ◽  
pp. 1119-1127 ◽  
Author(s):  
T. Nukada
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Structural Integrity ◽  
Brain Mitochondria ◽  
Sodium Ions ◽  
Glycine Uptake ◽  
Kidney Mitochondria ◽  
Rat Brain Mitochondria ◽  
Sodium Dependent

Rat brain mitochondrial pellets are able to accumulate glycine by a sodium-dependent and ouabain-sensitive process which is not potassium dependent. This process does not occur in liver or kidney mitochondria. Glycine uptake by brain mitochondria is not affected by the addition of ATP, NAD, or other cofactors, but it is inhibited by dinitrophenol and, competitively, by certain amino acids. Data obtained by the use of various concentrations of sodium ions or of sucrose indicate that the uptake of glycine by brain mitochondria is closely linked with their structural integrity.

scholarly journals Glutamate and aspartate transport in rat brain mitochondria

1974 ◽  
Vol 140 (2) ◽  
pp. 205-210 ◽  
Author(s):  
M. D. Brand ◽  
J. B. Chappell
Keyword(s):  
Rat Brain ◽  
Mitochondrial Membrane ◽  
Liver Mitochondria ◽  
Brain Mitochondria ◽  
Kidney Mitochondria ◽  
Pig Kidney ◽  
Rat Brain Mitochondria ◽  
Energy Dependent ◽  
Glutaminase Activity ◽  
Malate Aspartate Shuttle

1. Rat brain mitochondria did not swell in iso-osmotic solutions of ammonium or potassium (plus valinomycin) glutamate or aspartate, with or without addition of uncouplers. 2. Glutamate was able to reduce intramitochondrial NAD(P)+; aspartate was able to cause partial re-oxidation. 3. These effects were inhibited by threo-hydroxy-aspartate in whole but not in lysed mitochondria. 4. The existence of a ‘malate–aspartate shuttle’ for the oxidation of extramitochondrial NADH was demonstrated. This shuttle requires the net exchange of glutamate for aspartate across the mitochondrial membrane. 5. Extramitochondrial glutamate did not inhibit intramitochondrial glutaminase under conditions in which the inhibition in lysed mitochondria was virtually complete. 6. The glutaminase activity of these mitochondria was not energy-dependent. 7. We conclude that these mitochondria do not possess a glutamate–hydroxyl antiporter similar to that of liver mitochondria nor a glutamate–glutamine antiporter similar to that of pig kidney mitochondria, but that they do possess a glutamate–aspartate antiporter.

Acyl-CoA: sn-Glycerol-3-Phosphate O-Acyltransferase in Rat Brain Mitochondria and Microsomes

1982 ◽  
Vol 39 (1) ◽  
pp. 286-289 ◽  
Author(s):  
Susan M. Fitzpatrick ◽  
Giovanna Sorresso ◽  
Dipak Haldar
Keyword(s):  
Rat Brain ◽  
Brain Mitochondria ◽  
Rat Brain Mitochondria

scholarly journals The role of ADP in the modulation of the calcium-efflux pathway in rat brain mitochondria

1985 ◽  
Vol 225 (1) ◽  
pp. 41-49 ◽  
Author(s):  
J Vitorica ◽  
J Satrústegui
Keyword(s):  
Rat Brain ◽  
Binding Sites ◽  
Tricarboxylic Acid Cycle ◽  
Brain Mitochondria ◽  
Ruthenium Red ◽  
Calcium Efflux ◽  
Rat Brain Mitochondria ◽  
Pi Complex ◽  
Efflux Pathway

The role of ADP in the regulation of Ca2+ efflux in rat brain mitochondria was investigated. ADP was shown to inhibit Ruthenium-Red-insensitive H+- and Na+-dependent Ca2+-efflux rates if Pi was present, but had no effect in the absence of Pi. The primary effect of ADP is an inhibition of Pi efflux, and therefore it allows the formation of a matrix Ca2+-Pi complex at concentrations above 0.2 mM-Pi and 25 nmol of Ca2+/mg of protein, which maintains a constant free matrix Ca2+ concentration. ADP inhibition of Pi and Ca2+ efflux is nucleotide-specific, since in the presence of oligomycin and an inhibitor of adenylate kinase ATP does not substitute for ADP, is dependent on the amount of ADP present, and requires ADP concentrations in excess of the concentrations of translocase binding sites. Brain mitochondria incubated with 0.2 mM-Pi and ADP showed Ca2+-efflux rates dependent on Ca2+ loads at Ca2+ concentrations below those required for the formation of a Pi-Ca2+ complex, and behaved as perfect cytosolic buffers exclusively at high Ca2+ loads. The possible role of brain mitochondrial Ca2+ in the regulation of the tricarboxylic acid-cycle enzymes and in buffering cytosolic Ca2+ is discussed.

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