Abstract
Abstract Glutamine synthetase (L-glutamate: ammonia ligase (ADP) EC 6. 3. t 2) was prepared from cucumber leaves grown on ammonium medium and some regulative properties were investigated. The apparent Michaelis constant (Km) values of the various substrates and cofactors were determined. Lineweaver-Burk plots gave a Km of 4.5mM with L-glutamate, 0.74mM with ATP and 3.1 mM with NH2OH. Metals, including Cu2+, Hg2+, Zn2+, Ni2+, Fe2+, and Fe3+, strongly inhibited the enzyme activity, Cd2+ did not inhibit the enzyme activity markedly, in contrast with its effect on the rice enzyme. Ca2+ was quite inhibitive to enzyme reaction and more than 50% of the activity was lost at 3 mM. The amino acids tested generally had no effect on the enzyme activity except alanine, which showed little but clear inhibition. Isocitrate and α-ketoglutarate were slightly promotive to enzyme activity while pyruvate and glyoxylate (24 mM) significantly inhibited the enzyme activity. Glucose-l- or -6-phosphate and fructose-6-phosphate were inhibitive to similar degrees, about 20% at 22.5 mM, and 3-phosphoglycerate (22.5 mM) markedly inhibited the enzyme activity up to 56%. Among the nucleotides tested, UTP, CTP, and GTP inhibited slightly, and marked inhibitions of H and 78% were observed after the addition of AMP (5 mM) and ADP (5 mM) respectively. Pyridoxal-5′-phosphate, which is a characteristic incompetitive inhibitor of L-glutamate and NH2-OH, here inhibited enzyme activity significantly. On the other hand, pyridoxamine-5′-phosphate had almost no effect. The inhibition caused by the former was not recovered by the latter. This response of glutamine synthetase to both compounds was in agreement with the idea that the nitrogen status of the plant could be reflected by the ratio pyridoxamine phosphate/pyridoxal phosphate. Also this suggested that the regulative properties of glutamine synthetase with respect to pyridoxal or pyridoxamine phosphate could be understood from the point of view of the economical use of nitrogen.
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Claims 19
Claim · model-written summary
Cucumber leaf glutamine synthetase had a Km of 4.5mM with L-glutamate.
- Taxon
- cucumber
Cucumis sativust0 - Gene
- glutamine synthetaset0
- Compound
- L-glutamatee0
- Outcome
- Kme0
- Value
- 4.5mMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lineweaver-Burk plots gave a Km of 4.5mM with L-glutamate, 0.74mM with ATP and 3.1 mM with NH2OH.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
The Km was 0.74mM with ATP.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lineweaver-Burk plots gave a Km of 4.5mM with L-glutamate, 0.74mM with ATP and 3.1 mM with NH2OH.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
The Km was 3.1 mM with NH2OH.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lineweaver-Burk plots gave a Km of 4.5mM with L-glutamate, 0.74mM with ATP and 3.1 mM with NH2OH.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Cu2+, Hg2+ and Zn2+ strongly inhibited enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Cu2+, Hg2+, Zn2+e0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Metals, including Cu2+, Hg2+, Zn2+, Ni2+, Fe2+, and Fe3+, strongly inhibited the enzyme activity”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Ni2+, Fe2+ and Fe3+ strongly inhibited enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Ni2+, Fe2+, and Fe3+e0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Metals, including Cu2+, Hg2+, Zn2+, Ni2+, Fe2+, and Fe3+, strongly inhibited the enzyme activity”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Cd2+ did not markedly inhibit enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Cd2+e0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- did not inhibite0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd2+ did not inhibit the enzyme activity markedly, in contrast with its effect on the rice enzyme.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Ca2+ inhibited the reaction, with over half the activity lost at 3 mM.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Ca2+e0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme reactione0
- Direction
- loste0
- Value
- more than 50%e0
- Qualifier
- 3 mMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ca2+ was quite inhibitive to enzyme reaction and more than 50% of the activity was lost at 3 mM.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Tested amino acids generally had no effect on enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- amino acids testede0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amino acids tested generally had no effect on the enzyme activity except alanine, which showed little but clear inhibition.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Alanine caused slight clear inhibition.
- Taxon
- cucumberCucumis sativust0
- Treatment
- alaninee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The amino acids tested generally had no effect on the enzyme activity except alanine, which showed little but clear inhibition.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Isocitrate and α-ketoglutarate slightly promoted enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Isocitrate and α-ketoglutaratee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- promotivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Isocitrate and α-ketoglutarate were slightly promotive to enzyme activity”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Pyruvate and glyoxylate significantly inhibited enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- pyruvate and glyoxylatee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitede0
- Qualifier
- 24 mMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pyruvate and glyoxylate (24 mM) significantly inhibited the enzyme activity.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Glucose-l- or -6-phosphate and fructose-6-phosphate inhibited enzyme activity by about 20% at 22.5 mM.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Glucose-l- or -6-phosphate and fructose-6-phosphatee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitivee0
- Value
- about 20%e0
- Qualifier
- 22.5 mMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Glucose-l- or -6-phosphate and fructose-6-phosphate were inhibitive to similar degrees, about 20% at 22.5 mM, and 3-phosphoglycerate (22.5 mM) markedly inhibited the enzyme activity up to 56%.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
3-phosphoglycerate inhibited enzyme activity by up to 56%.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 3-phosphoglyceratee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitede0
- Value
- 56%e0
- Qualifier
- 22.5 mMe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3-phosphoglycerate (22.5 mM) markedly inhibited the enzyme activity up to 56%.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
UTP, CTP and GTP slightly inhibited enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- UTP, CTP, and GTPe0
- Gene
- glutamine synthetaset0
- Outcome
- glutamine synthetaset0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UTP, CTP, and GTP inhibited slightly”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
AMP produced marked inhibition, reported as H at 5 mM.
- Taxon
- cucumberCucumis sativust0
- Treatment
- AMP (5 mM)e0
- Gene
- glutamine synthetaset0
- Outcome
- glutamine synthetaset0
- Direction
- inhibitionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“marked inhibitions of H and 78% were observed after the addition of AMP (5 mM) and ADP (5 mM) respectively.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
ADP at 5 mM produced 78% inhibition.
- Taxon
- cucumberCucumis sativust0
- Treatment
- ADP (5 mM)e0
- Gene
- glutamine synthetaset0
- Outcome
- glutamine synthetaset0
- Direction
- inhibitionse0
- Value
- 78%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“marked inhibitions of H and 78% were observed after the addition of AMP (5 mM) and ADP (5 mM) respectively.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Pyridoxal-5′-phosphate significantly inhibited enzyme activity.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Pyridoxal-5′-phosphatee0
- Gene
- glutamine synthetaset0
- Outcome
- enzyme activitye0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pyridoxal-5′-phosphate, which is a characteristic incompetitive inhibitor of L-glutamate and NH2-OH, here inhibited enzyme activity significantly.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Pyridoxamine-5′-phosphate had almost no effect.
- Taxon
- cucumberCucumis sativust0
- Treatment
- pyridoxamine-5′-phosphatee0
- Gene
- glutamine synthetaset0
- Outcome
- glutamine synthetaset0
- Direction
- almost no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pyridoxamine-5′-phosphate had almost no effect.”
t0“glutamine synthetase in cucumber leaves”
Claim · model-written summary
Pyridoxamine-5′-phosphate did not reverse the inhibition caused by pyridoxal-5′-phosphate.
- Taxon
- cucumberCucumis sativust0
- Treatment
- pyridoxamine-5′-phosphatee0
- Gene
- glutamine synthetaset0
- Outcome
- inhibitione0
- Direction
- not recoverede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On the other hand, pyridoxamine-5′-phosphate had almost no effect. The inhibition caused by the former was not recovered by the latter.”
t0“glutamine synthetase in cucumber leaves”
The same questions in other papers
calcium(2+) · physiology: enzyme activity · Cucumis sativus (cucumber)Results agree
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- negative
copper(2+) · soil: biology · Cucumis sativus (cucumber)Results agree
1 paper in the same direction as this paper
- negative
iron(2+) · soil: biology · Cucumis sativus (cucumber)Results agree
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- 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.