scholarly journals Evidence for the sequential assembly of cytochrome oxidase subunits in rat liver mitochondria

1983 ◽  
Vol 212 (3) ◽  
pp. 829-834 ◽  
Author(s):  
A Wielburski ◽  
B D Nelson
Keyword(s):  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Temporal Sequence ◽  
Temporal Association ◽  
Rat Liver Mitochondria ◽  
Assembly Process ◽  
Isolated Rat Hepatocytes ◽  
Isolated Rat

The assembly of cytochrome oxidase was studied in isolated rat liver mitochondria and isolated rat hepatocytes labelled in vitro with L-[35S]methionine. This was achieved by studying the temporal association of radioactive subunits which are immunoabsorbed with antibodies against subunits I, II and the holoenzyme. Antibodies against the holoenzyme were shown to be highly specific for subunit V. The results show that subunit I appears in the holoenzyme late in the assembly process. No radioactive subunit I is absorbed with antiserum against subunit II or the holoenzyme (subunit V) after a 30 min pulse in either isolated mitochondria or hepatocytes. However, both antisera absorb radioactive subunits I after a 150 min chase in isolated hepatocytes. This was confirmed using antibodies against subunit I, which absorbed only radioactive subunit I after a 30 min pulse but absorbed radioactive subunits I-III and VI after a 150 min chase. Thus, the late assembly of radioactive subunit I is explained by a temporal sequence in the assembly process and not by the presence of a large, non-radioactive pool of subunit I. Using the above approach and the three specific antisera, the following temporal sequence in the assembly of cytochrome oxidase was established. Subunits II and III assemble rapidly with each other or with cytoplasmically translated subunit VI. This complex of three peptides in turn assembles slowly with subunit I or with the other cytoplasmically translated subunits. The early association of subunit VI with the mitochondrially translated subunits II and III suggests a possible role of the former in integration of the holoenzyme.

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930 ◽  
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Abstract Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

Succinic and Cytochrome Oxidase Activity of Rat Liver Mitochondria After in Vitro Irradiation With Ultraviolet Light

1957 ◽  
Vol 188 (3) ◽  
pp. 547-549 ◽  
Author(s):  
Attilio Canzanelli ◽  
Rhea Sossen ◽  
David Rapport
Keyword(s):  
Cytochrome Oxidase ◽  
Ultraviolet Light ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Biological Effects ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome Oxidase Activity ◽  
Order Of Magnitude

Five per cent suspensions of rat liver mitochondria were irradiated with ultraviolet light for varying periods of time and the succinoxidase and cytochrome oxidase activity were determined. Both succinoxidase and cytochrome oxidase activity were reduced by irradiation with ultraviolet. The order of magnitude of the ultraviolet energy necessary to produce such changes is much less than that necessary to produce chemical changes in nucleic acid derivatives, and approaches the amount which has been shown to produce lethal and other biological effects.

Hepatotoxic effect of (+)usnic acid from Usnea siamensis Wainio in rats, isolated rat hepatocytes and isolated rat liver mitochondria

2004 ◽  
Vol 90 (2-3) ◽  
pp. 381-387 ◽  
Author(s):  
Pornpen Pramyothin ◽  
Withaya Janthasoot ◽  
Nushjira Pongnimitprasert ◽  
Siriwan Phrukudom ◽  
Nijsiri Ruangrungsi
Keyword(s):  
Rat Liver ◽  
Usnic Acid ◽  
Rat Hepatocytes ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Hepatocytes ◽  
Isolated Rat Liver ◽  
Hepatotoxic Effect ◽  
Isolated Rat

scholarly journals Protein-mediated uptake of vitamin B12 by isolated mitochondria

Blood ◽  
1976 ◽  
Vol 47 (6) ◽  
pp. 923-930
Author(s):  
RA Gams ◽  
EM Ryel ◽  
F Ostroy
Keyword(s):  
Vitamin B12 ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Isolated Rat Liver ◽  
Isolated Mitochondria ◽  
Isolated Rat

Protein-mediated B12 uptake by isolated rat liver mitochondria has been shown to be enhanced by plasma transcobalamin (TC-II) but not by salivary R binder in vitro. The process is enhanced by calcium and depends on active mitochondrial respiration. Following uptake, cyanocobalamin is converted to adenosyl and methylcobalamins and released from the mitochondria. TC-II appears to be required for both cellular and mitochondrial uptake of vitamin B12.

Respiratory activity of isolated rat liver mitochondria following in vitro exposure to oxygen species: A threshold study

1990 ◽  
Vol 51 (3) ◽  
pp. 249-263 ◽  
Author(s):  
Philippe Corbisier ◽  
Martine Raes ◽  
Carine Michiels ◽  
Etienne Pigelolet ◽  
Andree Houbion ◽  
...  
Keyword(s):  
Rat Liver ◽  
Respiratory Activity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Oxygen Species ◽  
Isolated Rat Liver ◽  
In Vitro Exposure ◽  
Isolated Rat

scholarly journals Import of rat liver mitochondrial transhydrogenase

1988 ◽  
Vol 252 (3) ◽  
pp. 833-836 ◽  
Author(s):  
L N Y Wu ◽  
I M Lubin ◽  
R R Fisher
Keyword(s):  
Rat Liver ◽  
Proteinase Inhibitors ◽  
Rat Hepatocytes ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Translation System ◽  
Isolated Rat Hepatocytes ◽  
Matrix Fraction ◽  
Translation Mixture ◽  
Isolated Rat

The biosynthesis of pyridine dinucleotide transhydrogenase has been studied in isolated rat hepatocytes and in a rabbit reticulocyte-lysate translation system supplemented with either intact isolated rat liver mitochondria or the soluble matrix fraction from isolated mitochondria. In intact hepatocytes, the transhydrogenase precursor was short-lived in the cytosol and was efficiently imported into the membranous fraction. When the cell-free translation mixture was incubated with intact mitochondria, the transhydrogenase precursor was processed to the mature form, to an extent that depended on the amount of added mitochondria. Incubation of the translation mixture with the soluble mitochondria matrix fraction converted the precursor to a mature-sized protein with 75% efficiency, this being blocked by various proteinase inhibitors such as EDTA, 1,10-phenanthroline and leupeptin.

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