Abstract
Purified spinach (Spinacia oleracea) NADPH-preferring hydroxypyruvate reductase (HPR-2) was potently and selectively inhibited by oxalate, an end product of metabolism in plants. Both hydroxypyruvate- and glyoxylate-dependent rates of the HPR-2 enzyme were affected. Oxalate acted as an uncompetitive inhibitor of the enzyme, with Ki values of 7 and 36 microM for the NADPH/hydroxypyruvate and NADPH/glyoxylate pairs of reactants respectively. Oxalate, at millimolar levels, caused less than 10% inhibition of purified spinach NADH-preferring HPR (HPR-1) and had no effect on purified spinach NADPH-preferring glyoxylate-specific reductase (GR-1). The inhibition of spinach HPR-2 by oxalate is by far the strongest for any known inhibitor of leaf HPR and GR activities. In photosynthetic tissues, oxalate could potentially act as a primary regulator of extraperoxisomal metabolism of hydroxypyruvate and glyoxylate.
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Claims 6
Claim · model-written summary
Oxalate inhibited purified spinach HPR-2.
- Taxon
- spinach
Spinacia oleraceae0 - Treatment
- oxalatee0
- Gene
- NADPH-preferring hydroxypyruvate reductase (HPR-2)e0
- Outcome
- NADPH-preferring hydroxypyruvate reductase (HPR-2)e0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Purified spinach (Spinacia oleracea) NADPH-preferring hydroxypyruvate reductase (HPR-2) was potently and selectively inhibited by oxalate”
Claim · model-written summary
Oxalate inhibited HPR-2 hydroxypyruvate-dependent activity with Ki 7 microM.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- Oxalatee0
- Gene
- HPR-2e1
- Outcome
- NADPH/hydroxypyruvatee0
- Direction
- inhibitore0
- Value
- 7e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxalate acted as an uncompetitive inhibitor of the enzyme, with Ki values of 7 and 36 microM for the NADPH/hydroxypyruvate and NADPH/glyoxylate pairs of reactants respectively”
e1“spinach (Spinacia oleracea) NADPH-preferring hydroxypyruvate reductase (HPR-2)”
Claim · model-written summary
Oxalate inhibited HPR-2 glyoxylate-dependent activity with Ki 36 microM.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- Oxalatee0
- Gene
- HPR-2e1
- Outcome
- NADPH/glyoxylatee0
- Direction
- inhibitore0
- Value
- 36 microMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxalate acted as an uncompetitive inhibitor of the enzyme, with Ki values of 7 and 36 microM for the NADPH/hydroxypyruvate and NADPH/glyoxylate pairs of reactants respectively”
e1“spinach (Spinacia oleracea) NADPH-preferring hydroxypyruvate reductase (HPR-2)”
Claim · model-written summary
Millimolar oxalate caused less than 10% inhibition of spinach HPR-1.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- Oxalate, at millimolar levelse0
- Gene
- NADH-preferring HPR (HPR-1)e0
- Outcome
- inhibition of purified spinach NADH-preferring HPR (HPR-1)e0
- Direction
- inhibitione0
- Value
- less than 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxalate, at millimolar levels, caused less than 10% inhibition of purified spinach NADH-preferring HPR (HPR-1)”
Claim · model-written summary
Millimolar oxalate had no effect on spinach GR-1.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- Oxalate, at millimolar levelse0
- Gene
- NADPH-preferring glyoxylate-specific reductase (GR-1)e0
- Outcome
- NADPH-preferring glyoxylate-specific reductase (GR-1)e0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxalate, at millimolar levels, caused less than 10% inhibition of purified spinach NADH-preferring HPR (HPR-1) and had no effect on purified spinach NADPH-preferring glyoxylate-specific reductase (GR-1)”
Claim · model-written summary
The authors suggest oxalate could regulate extraperoxisomal hydroxypyruvate and glyoxylate metabolism in photosynthetic tissues.
- Taxon
- spinachSpinacia oleraceae1
- Organ / stage
- photosynthetic tissuese0
- Compound
- oxalatee0
- Outcome
- extraperoxisomal metabolism of hydroxypyruvate and glyoxylatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In photosynthetic tissues, oxalate could potentially act as a primary regulator of extraperoxisomal metabolism of hydroxypyruvate and glyoxylate”
e1“spinach (Spinacia oleracea)”
The same questions in other papers
oxalate · molecular: metabolites · Spinacia oleracea (spinach)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.