scholarly journals Subcellular localization of superoxide dismutase in rat liver

1975 ◽  
Vol 150 (1) ◽  
pp. 31-39 ◽  
Author(s):  
C Peeters-Joris ◽  
A M Vandevoorde ◽  
P Baudhuin
Keyword(s):  
Superoxide Dismutase ◽  
Subcellular Localization ◽  
Rat Liver ◽  
Specific Activity ◽  
Osmotic Shock ◽  
Superoxide Dismutase Activity ◽  
Mitochondrial Activity ◽  
Intermembrane Space ◽  
Matrix Space ◽  
The Matrix

The subcellular localization of superoxide dismutase was investigated in rat liver homogenates. Most of the superoxide dismutase activity is present in the soluble fraction (84%), the rest being associated with mitochondria. No indications for the occurrence of superoxide dismutase in other subcellular structures, particularly in peroxisomes, was found. Mitochondrial activity is not due to adsorption, since the sedimentable activity is essentially latent. Subfractionation of mitochondria by hypo-osmotic shock and sonication shows that half of the mitochondrial superoxide dismutase activity is localized in the intermembrane space, the rest of the enzyme being a component of the matrix space. In non-ionic media the matrix enzyme is, however, adsorbed to the inner membrane, from which it can be desorbed by low (0.04M) concentration of KCl. Superoxide dismutase activity was found in all rat organs investigated. Maximal activity of the enzyme is observed in liver, adrenals and kidney. In adrenals, the highest specific activity is associated with the medulla.

scholarly journals Polarographic assay and intracellular distribution of superoxide dismutase in rat liver.

1975 ◽  
Vol 147 (3) ◽  
pp. 493-504 ◽  
Author(s):  
D D Tyler
Keyword(s):  
Superoxide Dismutase ◽  
Rat Liver ◽  
Total Activity ◽  
Intracellular Distribution ◽  
Superoxide Dismutase Activity ◽  
Intermembrane Space ◽  
Matrix Space ◽  
Intracellular Location ◽  
H2o2 Formation ◽  
Mitochondrial Intermembrane Space

1. A polarographic assay of superoxide (O2-) dismutase (EC 1.15.1.1) activity is described, in which the ability of the enzyme to inhibit O2-dependent sulphite oxidation, initiated by xanthine oxidase activity, is measured. The assay was used in a study of the intracellular distribution of superoxide dismutase in rat liver. Both cyanide-sensitive cupro-zinc dismutase (92% of the total activity) and cyanide-insensitive mangano-dismutase (8%) were measured. 2. Rat liver homogenates contained both particulate (16%y and soluble (84%) dismutase activity. The particulate activity contained both types of dismutase, whereas nearly all the soluble dismutase was a cupro-zinc enzymes. The distribution pattern of mangano-dismutase was similar to that of cytochrome oxidase and glutamate dehydrogenase, indicating that the enzyme was probably present exclusively in the mitochondria. 3. Superoxide dismutase activity in the heavy-mitochondrial (M) fraction was latent and was activated severalfold and largely solubilized by sonication. Treatment of the M fraction with digitonin or a hypo-osmotic suspending medium indicated that most of the cupro-zinc dismutase was located in the mitochondrial intermembrane space, whereas the mangano-enzyme was located in the inner-membrane and matrix space. 4. A small amount of dismutase activity appeared to be present in the nuclei and microsomal fraction, but little or no activity in the lysosomes or peroxisomes. 5. The results are discussed in relation to the intracellular location of known O2-generating enzymes, the possible role of superoxide dismutase activity in intracellular H2O2 formation, and to current views on the physiological function of the enzyme.

Effects of estradiol benzoate and progesterone on superoxide dismutase activity in the rat liver

1997 ◽  
Vol 20 (4) ◽  
pp. 203-206 ◽  
Author(s):  
J. Kasapović ◽  
S. B. Pajović ◽  
D. T. Kanazir ◽  
J. V. Martinović
Keyword(s):  
Superoxide Dismutase ◽  
Rat Liver ◽  
Estradiol Benzoate ◽  
Superoxide Dismutase Activity

scholarly journals Rat liver mitochondrial ADP-ribose pyrophosphatase in the matrix space with low Km for free ADP-ribose

1994 ◽  
Vol 299 (3) ◽  
pp. 679-682 ◽  
Author(s):  
D Bernet ◽  
R M Pinto ◽  
M J Costas ◽  
J Canales ◽  
J C Cameselle
Keyword(s):  
Rat Liver ◽  
Gradient Centrifugation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Matrix Space ◽  
The Matrix ◽  
Submitochondrial Fractions

A study involving markers of subcellular and submitochondrial fractions, gradient centrifugation, latency measurements and extraction with digitonin, demonstrates the association of a specific ADP-ribose pyrophosphatase with rat liver mitochondria and its localization in the matrix space. The enzyme hydrolyses ADP-ribose to AMP, with a Km of 2-3 microM. The results support the occurrence of a specific turnover pathway for free ADP-ribose and its relevance in mitochondria.

scholarly journals Stable enhancement of calcium retention in mitochondria isolated from rat liver after the administration of glucagon to the intact animal

1978 ◽  
Vol 176 (3) ◽  
pp. 705-714 ◽  
Author(s):  
Veronica Prpić ◽  
Terry L. Spencer ◽  
Fyfe L. Bygrave
Keyword(s):  
Rat Liver ◽  
Molecular Mechanisms ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Mitochondrial Protein ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Matrix Space ◽  
The Matrix

1. Mitochondria isolated from rat liver by centrifugation of the homogenate in buffered iso-osmotic sucrose at between 4000 and 8000g-min, 1h after the administration in vivo of 30μg of glucagon/100g body wt., retain Ca2+ for over 45min after its addition at 100nmol/mg of mitochondrial protein in the presence of 2mm-Pi. In similar experiments, but after the administration of saline (0.9% NaCl) in place of glucagon, Ca2+ is retained for 6–8min. The ability of glucagon to enhance Ca2+ retention is completely prevented by co-administration of 4.2mg of puromycin/100g body wt. 2. The resting rate of respiration after Ca2+ accumulation by mitochondria from glucagon-treated rats remains low by contrast with that from saline-treated rats. Respiration in the latter mitochondria increased markedly after the Ca2+ accumulation, reflecting the uncoupling action of the ion. 3. Concomitant with the enhanced retention of Ca2+ and low rates of resting respiration by mitochondria from glucagon-treated rats was an increased ability to retain endogenous adenine nucleotides. 4. An investigation of properties of mitochondria known to influence Ca2+ transport revealed a significantly higher concentration of adenine nucleotides but not of Pi in those from glucagon-treated rats. The membrane potential remained unchanged, but the transmembrane pH gradient increased by approx. 10mV, indicating increased alkalinity of the matrix space. 5. Depletion of endogenous adenine nucleotides by Pi treatment in mitochondria from both glucagon-treated and saline-treated rats led to a marked diminution in ability to retain Ca2+. The activity of the adenine nucleotide translocase was unaffected by glucagon treatment of rats in vivo. 6. Although the data are consistent with the argument that the Ca2+-translocation cycle in rat liver mitochondria is a target for glucagon action in vivo, they do not permit conclusions to be drawn about the molecular mechanisms involved in the glucagon-induced alteration to this cycle.

scholarly journals Discrimination of distinct proteinases at the four structural levels of rat liver mitochondria

1986 ◽  
Vol 233 (1) ◽  
pp. 283-286 ◽  
Author(s):  
M C Duque-Magalhães ◽  
P Régnier
Keyword(s):  
Outer Membrane ◽  
Rat Liver ◽  
Degradation Products ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Intermembrane Space ◽  
Peptidase Activity ◽  
Inner Membrane ◽  
Mitochondrial Fractions ◽  
The Matrix

Rat liver mitochondrial fractions corresponding to four morphological structures (matrix, inner membrane, intermembrane space and outer membrane) contain proteinases that cleave casein components at different rates. Proteinases of the intermembrane space preferentially cleave kappa-casein, whereas the proteinases of the outer membrane, inner membrane and matrix fractions degrade alpha S1-casein more rapidly. Electrophoretic separation of the degradation products of alpha S1-casein and kappa-casein in polyacrylamide gels shows that different polypeptides are produced when the substrate is degraded by the matrix, by both membranes and by the intermembrane-space fraction. Some of the degradation products resulting from incubation of the caseins with the mitochondrial fractions are probably the result of digestion by contaminating lysosomal proteinase(s). The matrix has a high peptidase activity, since glucagon, a small peptide, is very rapidly degraded by this fraction. These observations strongly suggest that distinct proteinases, with different specificities, are associated respectively with the intermembrane space and with both membrane fractions.

Influence of adrenalectomy and dexamethasone on rat liver metallothionein and superoxide dismutase activity

1984 ◽  
Vol 91 (2) ◽  
pp. L21-L22 ◽  
Author(s):  
Linda L. Hutchings ◽  
Diane M. Scholler ◽  
Joan S. Valentine ◽  
Mavis R. Swerdel ◽  
Kenneth R. Etzel ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Rat Liver ◽  
Superoxide Dismutase Activity
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