FACTORS INFLUENCING THE UTILIZATION OF REDUCED NICOTINAMIDE ADENINE DINUCLEOTIDE BY PIGEON HEART MITOCHONDRIA

1966 ◽  
Vol 44 (1) ◽  
pp. 105-117 ◽  
Author(s):  
Marcel C. Blanchaer ◽  
Carl-Göran Lundquist ◽  
Thomas J. Griffith
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Respiratory Control ◽  
Zero Order ◽  
Nadh Oxidation ◽  
Heart Mitochondria ◽  
Nicotinamide Adenine ◽  
Carbohydrate Utilization ◽  
Factors Influencing ◽  
Zero Order Kinetics ◽  
Reduced Nicotinamide Adenine Dinucleotide

Pigeon heart mitochondria that were studied exhibited ADP:O and respiratory control ratios of 2.3–3.1 and 6–20 respectively with glutamate as substrate. This coupled respiration of glutamate was reversibly inhibited by ATP. In polarographic and photometric experiments at 28° in a medium containing 0.23 M mannitol, 0.07 M sucrose, 0.02 M Tris, and 0.02 mM EDTA at pH 7.2 such mitochondria oxidized 15–150 μM NADH with essentially zero order kinetics and an apparent Km of approximately 4 μM. NADH oxidation, which was not coupled to phosphorylation, was increased 50% by the addition of 5 mM orthophosphate (Pi) but was inhibited by albumin, NAD, ATP, and ADP. The effect of NAD became marked only at concentrations of 2–5 mM. However, ATP in concentrations (5–10 mM) similar to those found in heart, inhibited by 50–75% the oxidation of physiological levels (~ 10 μM) of NADH. These and other findings are compatible with the view that the oxidation of cytoplasmic NADH is a normal property of heart mitochondria, and that the control of this process by changes in the intracellular levels of ATP and Pi may influence myocardial carbohydrate utilization.

CONTROL OF REDUCED NICOTINAMIDE-ADENINE DINUCLEO-TIDE OXIDATION BY PIGEON-HEART MITOCHONDRIA

1966 ◽  
Vol 44 (11) ◽  
pp. 1527-1537 ◽  
Author(s):  
M. C. Blanchaer ◽  
Thomas J. Griffith
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Adenine Nucleotide ◽  
Respiratory Control ◽  
Adenosine Diphosphate ◽  
Nadh Oxidation ◽  
Heart Mitochondria ◽  
Nicotinamide Adenine ◽  
Nucleotide Inhibition ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
A Site

The rate of oxidation of 10–35 μM reduced nicotinamide–adenine dinucleotide (NADH) by pigeon-heart mitochondria was increased not only by osmotic swelling and sonic disruption of the organelles but also by milder procedures such as washing or dilution, which had no deleterious effect on the P: O and respiratory control ratios when glutamate was the substrate. In all cases, the enhanced oxidation of 10 μM NADH was suppressed by 5 mM adenosine triphosphate (ATP). From these and other findings it was concluded that the access of extra-mitochondrial NADH to the respiratory chain is controlled at a minimum of two sites. Control of NADH flux through the first site is lost after treatment of the mitochondria by procedures which increase their permeability. A second level of NADH control survives sonic disruption of the mitochondria and is a site at which the oxidation of 10 μM NADH is stimulated by Pi and inhibited by ATP, adenosine diphosphate (ADP), and oxidized nicotinamide–adenine dinucleotide (NAD+). The ATP and ADP effects at this level are not blocked by oligomycin. Magnesium releases the adenine nucleotide inhibition of NADH oxidation under certain conditions, but its site and mode of action is not clear as yet. In these experiments, NADH oxidation was determined polarographically and photometrically at 28° in a medium containing 0.23 M mannitol, 0.07 M sucrose, 0.02 M Tris–chloride, and 0.02 mM ethylenediamine tetra-acetic acid (EDTA) at pH 7.2.

scholarly journals Transport of reduced nicotinamide–adenine dinucleotide into mitochondria of rat white adipose tissue

1970 ◽  
Vol 116 (2) ◽  
pp. 229-233 ◽  
Author(s):  
B. H. Robinson ◽  
M. L. Halperin
Keyword(s):  
Adipose Tissue ◽  
Rat Liver ◽  
White Adipose Tissue ◽  
Nicotinamide Adenine Dinucleotide ◽  
Aspartate Aminotransferase ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Nadh Oxidation ◽  
Rat Liver Mitochondria ◽  
Reduced Nicotinamide Adenine Dinucleotide

Mitochondria from rat white adipose tissue were prepared, exhibiting good respiratory control and P/O ratios. They would not oxidize NADH unless NNN′N′-tetramethyl-p-phenylenediamine was added as a carrier of reducing equivalents. These mitochondria were found to oxidize neither l-glycerol 3-phosphate nor l-glutamate plus l-malate at significant rates. The activity of aspartate aminotransferase in these mitochondria was found to be low compared with that found in rat liver mitochondria. As a consequence of this, the adipose-tissue mitochondria exhibited very low rates of cytoplasmic NADH oxidation in a reconstituted Borst (1962) cycle compared with liver mitochondria.

NAD/NADH: redox state changes on cat brain cortex during stimulation and hypercapnia

1982 ◽  
Vol 243 (4) ◽  
pp. H619-H627 ◽  
Author(s):  
L. Gyulai ◽  
E. Dora ◽  
A. G. Kovach
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Redox State ◽  
Redox System ◽  
Inhibitory Effect ◽  
Nadh Oxidation ◽  
Nicotinamide Adenine ◽  
Direct Inhibitory Effect ◽  
Anterior Suprasylvian Gyrus ◽  
Reduced Nicotinamide Adenine Dinucleotide

The redox state of the anterior suprasylvian gyrus of cats was measured during electrical stimulation and under hypercapnia on cast immobilized and artificially respirated. The state of the nicotinamide adenine dinucleotide-reduced nicotinamide adenine dinucleotide (NAD/NADH) redox system was monitored by in vivo fluorometry. Hypercapnia was produced by inhalation of 10, 15, and 30% CO2, respectively. Hypercapnic acidosis led to NADH oxidation. The NADH oxidation under 30% CO2 inhalation was significantly larger (-14.9 +/- 2.9%) than that observed under 10% (-6.5 +/- 1.9%) and 15% CO2 (-7.0 +/- 1.6%) inhalation. Under normocapnic conditions, stimulation induced NAD reduction to NADH (5.5 +/- 0.8%). The magnitude of the NAD reductive response to stimulation was unaffected by 10% CO2 inhalation, but it was decreased by 15 and 30% CO2 inhalation. The increased concentration of NADH upon stimulation is interpreted as resulting from an increased rate of substrate mobilization. The cause of the oxidation of the NADH pool of the cell during hypercapnia is partly due to the direct inhibitory effect of CO2 on the carbohydrate metabolism, but the role of other mechanisms cannot be neglected either.

FACTORS INFLUENCING TETRAZOLE REDUCTION BY REDUCED NICOTINAMIDE–ADENINE DINUCLEOTIDE IN PIGEON-HEART MITOCHONDRIA

1967 ◽  
Vol 45 (2) ◽  
pp. 299-307 ◽  
Author(s):  
C. L. Talesara ◽  
M. C. Blanchaer
Keyword(s):  
Adenosine Triphosphate ◽  
Respiratory Chain ◽  
Nicotinamide Adenine Dinucleotide ◽  
Inorganic Phosphate ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Heart Mitochondria ◽  
Nicotinamide Adenine ◽  
Tetrazolium Chloride ◽  
Reduced Nicotinamide Adenine Dinucleotide

The effect of adenosine triphosphate, adenosine diphosphate, adenosine monophosphate and inorganic phosphate on the reduction of 2-(p-iodophenyi)-3-p-nitrophenyl-5-phenyl tetrazolium chloride (INT) to its formazan by reduced nicotinamide-adenine dinucleotide (NADH) was studied in pigeon-heart mitochondria. Formazan production was followed at 540 mμ in 2.2 ml medium containing 0.4–0.5 mg mitochondrial protein, 0.22 M mannitol, 0.067 M sucrose, 0.02 M Tris–chloride, 0.02 mM EDTA, 0.5–3.0 mM INT, and 38 μM NADH at pH 7.2 and 28 °C. By means of the respiratory inhibitors Amytal, rotenone, antimycin A, and cyanide, it was shown that INT diverts electrons from the respiratory chain principally at the flavoprotein level. In contrast to its inhibitory effect on "the O2-linked oxidation of NADH, 10 mM adenosine triphosphate stimulated the reaction rate and formazan yield in the present system. Equimolar inorganic phosphate also increased the initial velocity but adenosine diphosphate and adenosine monophosphate did not. Preliminary kinetic studies suggest that NADH, but not INT, combines with the form of NADH dehydrogenase in the respiratory chain with which adenosine triphosphate reacts.

Reduced nicotinamide adenine dinucleotide and depolarization in neurons

1975 ◽  
Vol 228 (4) ◽  
pp. 996-1001 ◽  
Author(s):  
C Rodriguez-Estrada
Keyword(s):  
Respiratory Chain ◽  
Nicotinamide Adenine Dinucleotide ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Nadh Oxidation ◽  
Nicotinamide Adenine ◽  
Similar Response ◽  
Phosphate Potential ◽  
Ganglion Neurons ◽  
Reduced Nicotinamide Adenine Dinucleotide

Activity of frog dorsal root ganglion neurons, evoked by dorsal root stimulation under aerobic conditions, produced a change in the level of reduced nicotinamide adenine dinucleotide (NADH) on the surface of this tissue. There was a decrease of NADH (oxidation), followed by an increase of NADH (reduction). Both changes were dependent on previous activity, and a critical time is required in order to observe a similar response. At the frequency and duration of stimulation used here, each stimulus evoked neuron depolarization as shown by recording from single cells. The NADH oxidation occurred in the respiratory chain and it was selectively blocked by Amytal. The NAD reduction was attributed to 3-phosphoglyceraldehyde dehydrogenase activity and it was blocked by iodoacetate. The NADH oxidation and NAD reduction were attributed to respiratory chain activity and aerobic glycolysis, both activated and deactivated by changes of phosphate potential (ATP/ADP + Pi). A low phosphate potential activates the respiratory chain and glycolysis; a high phosphate potential deactivates the respiratory chain and glycolysis.

scholarly journals The interaction of reduced nicotinamide–adenine dinucleotide phosphate with reduced nicotinamide–adenine dinucleotide–ubiquinone reductase from bovine heart mitochondria

1976 ◽  
Vol 158 (1) ◽  
pp. 149-151 ◽  
Author(s):  
C I Ragan
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Heart Mitochondria ◽  
Nicotinamide Adenine ◽  
Bovine Heart ◽  
Reduced Nicotinamide Adenine Dinucleotide

Reduction of the chromophores of mitochondrial NADH-ubiquinone reductase by NADPH reaches only 50% of the extent of reduction by NADH, monitored at 450 nm. This effect is due to autoxidation of an enzyme component at a higher rate than its reduction by NADPH.

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