Abstract
Preincubation of potato (Solanum tuberosum) tuber mitochondria with 300 microM-H2O2 for 10 min nearly stopped the State 3 rate of citrate oxidation. Addition of isocitrate resulted in resumption of O2 uptake. The State 3 rates of succinate, external NADH and 2-oxoglutarate oxidation were unaffected by H2O2 over the dose range 50-500 microM. Preincubation of mitochondria with 300 microM-H2O2 for 5 min unmasked in the matrix space a paramagnetic signal with a peak at a g value of approx. 2.03. Aconitase was purified over 135-fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria. The native enzyme was composed of a single polypeptide chain (molecular mass 90 kDa). Incubation of purified aconitase with small amounts of H2O2 caused the build up of a paramagnetic 3Fe cluster with a low-field maximum of g = 2.03 leading to a progressive inhibition of aconitase activity. The results show that aconitase present in the matrix space was the major intramitochondrial target for inactivation by H2O2.
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Claims 9
Claim · model-written summary
Hydrogen peroxide nearly stopped State 3 citrate oxidation in potato tuber mitochondria.
- Taxon
- potato
Solanum tuberosume0 - Organ / stage
- tubere0
- Treatment
- 300 microM-H2O2 for 10 mine0
- Outcome
- State 3 rate of citrate oxidatione0
- Direction
- nearly stoppede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Preincubation of potato (Solanum tuberosum) tuber mitochondria with 300 microM-H2O2 for 10 min nearly stopped the State 3 rate of citrate oxidation”
Claim · model-written summary
Adding isocitrate resumed oxygen uptake.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- isocitratee0
- Outcome
- O2 uptakee0
- Direction
- resumptione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of isocitrate resulted in resumption of O2 uptake”
e1“potato (Solanum tuberosum) tuber mitochondria”
Claim · model-written summary
Hydrogen peroxide did not affect State 3 oxidation of succinate, external NADH, or 2-oxoglutarate over 50–500 microM.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- H2O2e0
- Outcome
- State 3 rates of succinate, external NADH and 2-oxoglutarate oxidatione0
- Direction
- unaffectede0
- Qualifier
- 50-500 microMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The State 3 rates of succinate, external NADH and 2-oxoglutarate oxidation were unaffected by H2O2 over the dose range 50-500 microM”
e1“potato (Solanum tuberosum) tuber mitochondria”
Claim · model-written summary
Peroxide exposure unmasked a matrix paramagnetic signal near g 2.03.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- 300 microM-H2O2 for 5 mine0
- Outcome
- paramagnetic signale0
- Value
- approx. 2.03e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Preincubation of mitochondria with 300 microM-H2O2 for 5 min unmasked in the matrix space a paramagnetic signal with a peak at a g value of approx. 2.03”
e1“potato (Solanum tuberosum) tuber mitochondria”
Claim · model-written summary
Purified potato mitochondrial aconitase attained 32 mumol/min per mg specific activity after over 135-fold purification.
- Taxon
- potatoSolanum tuberosume0
- Organ / stage
- tubere0
- Gene
- Aconitasee0
- Outcome
- specific activitye0
- Value
- 32 mumol/min per mge0
- Qualifier
- over 135-folde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aconitase was purified over 135-fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria”
Claim · model-written summary
Native potato mitochondrial aconitase was one 90 kDa polypeptide chain.
- Taxon
- potatoSolanum tuberosume1
- Gene
- Aconitasee1
- Outcome
- single polypeptide chaine0
- Value
- 90 kDae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The native enzyme was composed of a single polypeptide chain (molecular mass 90 kDa)”
e1“Aconitase was purified over 135-fold to a specific activity of 32 mumol/min per mg (with isocitrate as substrate) from the matrix of potato tuber mitochondria”
Claim · model-written summary
Peroxide caused a paramagnetic 3Fe cluster to build up in purified aconitase.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- small amounts of H2O2e0
- Gene
- aconitasee0
- Outcome
- paramagnetic 3Fe clustere0
- Value
- g = 2.03e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Incubation of purified aconitase with small amounts of H2O2 caused the build up of a paramagnetic 3Fe cluster with a low-field maximum of g = 2.03”
e1“potato tuber mitochondria”
Claim · model-written summary
Peroxide progressively inhibited purified aconitase activity.
- Taxon
- potatoSolanum tuberosume1
- Treatment
- small amounts of H2O2e0
- Gene
- aconitasee0
- Outcome
- aconitase activitye0
- Direction
- inhibitione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Incubation of purified aconitase with small amounts of H2O2 caused the build up of a paramagnetic 3Fe cluster with a low-field maximum of g = 2.03 leading to a progressive inhibition of aconitase activity”
e1“potato tuber mitochondria”
Claim · model-written summary
The authors identify matrix aconitase as the major intramitochondrial peroxide inactivation target.
- Taxon
- potatoSolanum tuberosume1
- Gene
- aconitasee0
- Outcome
- major intramitochondrial target for inactivation by H2O2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“aconitase present in the matrix space was the major intramitochondrial target for inactivation by H2O2”
e1“potato tuber mitochondria”
The same questions in other papers
hydrogen peroxide · molecular: metabolites · Solanum tuberosum (potato)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.