Characterization of frog muscle mitochondria

1978 ◽  
Vol 234 (1) ◽  
pp. C1-C6 ◽  
Author(s):  
C. Skoog ◽  
U. Kromer ◽  
R. W. Mitchell ◽  
J. Hoogstraten ◽  
N. L. Stephens
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Mitochondrial Protein ◽  
Frog Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Nadh Oxidase Activity ◽  
Phosphorylation Rate

Studies on oxidative phosphorylation revealed that, in frog skeletal muscle mitochondria (SKMM) from the thigh, the adenosine diphosphate/oxygen ratio (ADP/O) was 2.8 +/- 0.1 SE, and the respiratory control ratio was 9.5 +/- 0.9, with pyruvate/malate as the substrate. Oxygen uptake rate (Qo2) was 225 mumol O2 per minute per gram mitochondrial protein +/- 13; phosphorylation rate (ADP/O X Qo2 X 2) was 1,230 mumol ADP phosphorylation per minute per gram mitochondrial protein +/- 77; and the phosphorylation capacity (phosphorylation rate times tissue mitochondrial protein content) was 3.6 mumol ADP phosphorylated per gram wet weight of muscle +/- 0.2. Tissue mitochondrial protein content was determined by the measurement of nicotinamide adenine dinucleotide (NADH) oxidase activity. Electron microscopy (EM) revealed intact, isolated, energized twisted mitochondria of a condensed form. Frog sartorius muscle mitochondria gave similar oxidative phosphorylation parameters when investigated independently of the rest of the thigh. These values of SKMM respiration from the frog are similar to those values obtained from pigeon and rabbit heart and rat skeletal muscles. However, because of the low NADH-oxidase activity indicating reduced mitochondrial content (this was verified in low-magnification EM pictures), phosphorylation capacity was significantly reduced in frog skeletal muscle mitochondria.

65 Fatty acid oxidation in human skeletal muscle mitochondria determined by oxidative phosphorylation as a function of age

Mitochondrion ◽  
2007 ◽  
Vol 7 (6) ◽  
pp. 422-423
Author(s):  
George Kypriotakis ◽  
Bruce H. Cohen ◽  
Sumit Parikh ◽  
Douglas S. Kerr ◽  
Charles L. Hoppel ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Oxidative Phosphorylation ◽  
Fatty Acid Oxidation ◽  
Human Skeletal Muscle ◽  
Acid Oxidation ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria

Artifactual uncoupling by uncoupling protein 3 in yeast mitochondria at the concentrations found in mouse and rat skeletal-muscle mitochondria

2001 ◽  
Vol 361 (1) ◽  
pp. 49-56 ◽  
Author(s):  
James A. HARPER ◽  
Jeff A. STUART ◽  
Mika B. JEKABSONS ◽  
Damien ROUSSEL ◽  
Kevin M. BRINDLE ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Uncoupling Protein ◽  
Mitochondrial Protein ◽  
Yeast Mitochondria ◽  
Rat Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Uncoupling Protein 3 ◽  
Brown Adipose

Western blots detected uncoupling protein 3 (UCP3) in skeletal-muscle mitochondria from wild-type but not UCP3 knock-out mice. Calibration with purified recombinant UCP3 showed that mouse and rat skeletal muscle contained 0.14μg of UCP3/mg of mitochondrial protein. This very low UCP3 content is 200–700-fold less than the concentration of UCP1 in brown-adipose-tissue mitochondria from warm-adapted hamster (24–84μg of UCP1/mg of mitochondrial protein). UCP3 was present in brown-adipose-tissue mitochondria from warm-adapted rats but was undetectable in rat heart mitochondria. We expressed human UCP3 in yeast mitochondria at levels similar to, double and 7-fold those found in rodent skeletal-muscle mitochondria. Yeast mitochondria containing UCP3 were more uncoupled than empty-vector controls, particularly at concentrations that were 7-fold physiological. However, uncoupling by UCP3 was not stimulated by the known activators palmitate and superoxide; neither were they inhibited by GDP, suggesting that the observed uncoupling was a property of non-native protein. As a control, UCP1 was expressed in yeast mitochondria at similar concentrations to that of UCP3 and at up to 50% of the physiological level of UCP1. Low levels of UCP1 gave palmitate-dependent and GDP-sensitive proton conductance but higher levels of UCP1 caused an additional GDP-insensitive uncoupling artifact. We conclude that the uncoupling of yeast mitochondria by high levels of UCP3 expression is entirely an artifact and provides no evidence for any native uncoupling activity of the protein.

The Effect of Sodium and Potassium on Calcium Uptake by Frog Skeletal Muscle Mitochondria and Vesicles

1972 ◽  
Vol 50 (12) ◽  
pp. 1157-1161 ◽  
Author(s):  
Satish Batra
Keyword(s):  
Skeletal Muscle ◽  
Calcium Uptake ◽  
Frog Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Sucrose Medium ◽  
Ca Uptake ◽  
Sodium And Potassium

Calcium uptake by mitochondria of frog skeletal muscle increased when K replaced Na or sucrose in the medium. There was no difference in passive binding of Ca and the amount of ATP split when K replaced Na. Ca uptake was increased by substituting K for Na in the medium and was maximal in a medium containing 100 mM K and no Na. Azide and dinitrophenol (DNP) inhibited K-stimulated Ca uptake completely. Inhibition by these agents in Na medium was relatively small. Ca uptake by vesicles was little affected by changing from Na to K medium, by azide, or by DNP. Ageing reduced Ca uptake in both fractions and stimulation by K of mitochondrial Ca uptake nearly disappeared after 4 h of storage (at 4 °C). Since Ca was taken up to the same extent in Na or sucrose medium, it is concluded that Ca uptake by mitochondria is stimulated by K rather than inhibited by Na.

A magnesium-responsive defect of respiration and oxidative phosphorylation in skeletal muscle mitochondria of dystrophic hamsters

1970 ◽  
Vol 48 (12) ◽  
pp. 1332-1338 ◽  
Author(s):  
K. Wrogemann ◽  
M. C. Blanchaer ◽  
B. E. Jacobson
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Respiratory Rate ◽  
Test System ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Muscle Necrosis ◽  
Presence And Absence ◽  
Stimulation Of

Skeletal muscle mitochondria were isolated in the presence and absence of the proteinase Nagarse from dystrophic hamsters of the BIO 14.6 strain, aged 45–196 days, and from normal hamsters. Mitochondria from the dystrophic animals prepared by glass-on-glass homogenization without Nagarse in 0.25 M sucrose – 1 mM EDTA, pH 7.4, did not differ from normal in their respiratory rate or capacity for oxidative phosphorylation. However, these functions were subnormal in mitochondria isolated with Nagarse from the same animals, both in the presence and absence of albumin. Respiration measured with an O2 electrode was reduced by 50–70% and the stimulation of O2 uptake normally seen after ADP addition was minimal or absent. This was most marked in mitochondria from young hamsters about 65 days old with muscle necrosis. The defect was ameliorated by addition to the Polarographie test system of an ATP trap or of Mg2+, one of the trap constituents. This ion, when added to the defective mitochondria prior to ADP and substrate, restored respiration and oxidative phosphorylation to values that did not differ significantly from those found with skeletal muscle mitochondria of normal hamsters.

scholarly journals Effect of Calcium on the Oxidative Phosphorylation Cascade in Skeletal Muscle Mitochondria

Biochemistry ◽  
2013 ◽  
Vol 52 (16) ◽  
pp. 2793-2809 ◽  
Author(s):  
Brian Glancy ◽  
Wayne T. Willis ◽  
David J. Chess ◽  
Robert S. Balaban
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Phosphorylation ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Phosphorylation Cascade

scholarly journals Reversible phosphorylation of pyruvate dehydrogenase in rat skeletal-muscle mitochondria. Effects of starvation and diabetes

1984 ◽  
Vol 219 (2) ◽  
pp. 635-646 ◽  
Author(s):  
S J Fuller ◽  
P J Randle
Keyword(s):  
Skeletal Muscle ◽  
Pyruvate Dehydrogenase ◽  
Alloxan Diabetes ◽  
Active Form ◽  
Mitochondrial Protein ◽  
Total Activity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria

The total activity of pyruvate dehydrogenase (PDH) complex in rat hind-limb muscle mitochondria was 76.4 units/g of mitochondrial protein. The proportion of complex in the active form was 34% (as isolated), 8-14% (incubation with respiratory substrates) and greater than 98% (incubation without respiratory substrates). Complex was also inactivated by ATP in the presence of oligomycin B and carbonyl cyanide m-chlorophenylhydrazone. Ca2+ (which activates PDH phosphatase) and pyruvate or dichloroacetate (which inhibit PDH kinase) each increased the concentration of active PDH complex in a concentration-dependent manner in mitochondria oxidizing 2-oxoglutarate/L-malate. Values giving half-maximal activation were 10 nM-Ca2+, 3 mM-pyruvate and 16 microM-dichloroacetate. Activation by Ca2+ was inhibited by Na+ and Mg2+. Mitochondria incubated with [32P]Pi/2-oxoglutarate/L-malate incorporated 32P into three phosphorylation sites in the alpha-chain of PDH; relative rates of phosphorylation were sites 1 greater than 2 greater than 3, and of dephosphorylation, sites 2 greater than 1 greater than 3. Starvation (48h) or induction of alloxan-diabetes had no effect on the total activity of PDH complex in skeletal-muscle mitochondria, but each decreased the concentration of active complex in mitochondria oxidizing 2-oxoglutarate/L-malate and increased the concentrations of Ca2+, pyruvate or dichloracetate required for half-maximal reactivation. In extracts of mitochondria the activity of PDH kinase was increased 2-3-fold by 48 h starvation or alloxan-diabetes, but the activity of PDH phosphatase was unchanged.

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