Abstract
The general mitochondrial processing peptidase that removes the N-terminal targeting signals from proteins imported into mitochondria forms part of a respiratory protein complex in potato (Solanum tuberosum L.). We have termed this complex the "cytochrome c reductase/processing peptidase complex" and show that it acts on a variety of precursor proteins from different intramitochondrial locations. In potato, biochemical methods fail to separate the ubiquinol cytochrome c oxidoreductase function from the function of the processing protease. On the other hand, inhibition of electron flow with antimycin A or myxothiazol does not affect processing activity. The integration into an oligomeric protein complex causes the unique properties of the processing enzyme. It is fully active at high pH and in the presence of high salt. It does not need externally added metal ions, but it is inhibited by EDTA and 1,10-phenanthroline. Other protease inhibitors have no effect on the processing activity. Taken together, the molecular genetic and physiological results indicate that the mitochondrial processing protease does not belong to the thermolysin superfamily of metalloproteinases but may be a member of a new class of metalloendoproteases.
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Claims 8
Claim · model-written summary
The potato complex processes precursor proteins from multiple mitochondrial locations.
- Taxon
- Potato
Solanum tuberosumt0 - Gene
- cytochrome c reductase/processing peptidase complexe0
- Outcome
- acts on a variety of precursor proteins from different intramitochondrial locationse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We have termed this complex the "cytochrome c reductase/processing peptidase complex" and show that it acts on a variety of precursor proteins from different intramitochondrial locations.”
t0“Potato Mitochondria”
Claim · model-written summary
Biochemical methods did not separate the complex’s respiratory and processing activities.
- Taxon
- potatoSolanum tuberosume0
- Outcome
- fail to separate the ubiquinol cytochrome c oxidoreductase function from the function of the processing proteasee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In potato, biochemical methods fail to separate the ubiquinol cytochrome c oxidoreductase function from the function of the processing protease.”
Claim · model-written summary
Electron flow inhibitors did not affect processing activity.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- antimycin A or myxothiazole0
- Outcome
- processing activitye0
- Direction
- does not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inhibition of electron flow with antimycin A or myxothiazol does not affect processing activity”
t0“Potato Mitochondria”
Claim · model-written summary
The processing enzyme remained fully active at high pH and salt.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- fully activee0
- Qualifier
- high pH and in the presence of high salte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is fully active at high pH and in the presence of high salt.”
t0“Potato Mitochondria”
Claim · model-written summary
The enzyme did not require externally added metal ions.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- does not need externally added metal ionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It does not need externally added metal ions, but it is inhibited by EDTA and 1,10-phenanthroline.”
t0“Potato Mitochondria”
Claim · model-written summary
EDTA and 1,10-phenanthroline inhibited the processing enzyme.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- EDTA and 1,10-phenanthrolinee0
- Outcome
- ite0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it is inhibited by EDTA and 1,10-phenanthroline.”
t0“Potato Mitochondria”
Claim · model-written summary
Other protease inhibitors did not affect processing activity.
- Taxon
- PotatoSolanum tuberosumt0
- Treatment
- Other protease inhibitorse0
- Outcome
- processing activitye0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Other protease inhibitors have no effect on the processing activity.”
t0“Potato Mitochondria”
Claim · model-written summary
The authors place the enzyme outside the thermolysin superfamily and suggest a new metalloendoprotease class.
- Taxon
- PotatoSolanum tuberosumt0
- Outcome
- does not belong to the thermolysin superfamily of metalloproteinases but may be a member of a new class of metalloendoproteasese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the mitochondrial processing protease does not belong to the thermolysin superfamily of metalloproteinases but may be a member of a new class of metalloendoproteases.”
t0“Potato Mitochondria”