Abstract
The effects of 1 millimolar glyphosate (N-[phosphonomethyl]glycine) upon the activities of enzymes of aromatic amino acid biosynthesis, partially purified by ion-exchange chromatography from mung bean seedings (Vigna radiata [L.] Wilczek), were examined. Multiple isozyme species of shikimate dehydrogenase, chorismate mutase, and aromatic aminotransferase were separated, and these were all insensitive to inhibition by glyphosate. The activities of prephenate dehydrogenase and arogenate dehydrogenase were also not sensitive to inhibition. Two molecular species of 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase were resolved, one stimulated several-fold by Mn(2+) (DAHP synthase-Mn), and the other absolutely dependent upon the presence of Co(2+) for activity (DAHP synthase-Co). Whereas DAHP synthase-Mn was invulnerable to glyphosate, greater than 95% inhibition of DAHP synthase-Co was found in the presence of glyphosate. Since Co(2+) is a V(max) activator with respect to both substrates, glyphosate cannot act simply by Co(2+) chelation because inhibition is competitive with respect to erythrose-4-phosphate. The accumulation of shikimate found in glyphosate-treated seedlings is consistent with in vivo inhibition of both 5-enolpyruvylshikimic acid 3-phosphate synthase and one of the two DAHP synthase isozymes. Aromatic amino acids, singly or in combination, only showed a trend towards reversal of growth inhibition in 7-day seedlings of mung bean. The possibilities are raised that glyphosate may act at multiple enzyme targets in a given organism or that different plants may vary in the identity of the prime enzyme target.
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Claims 5
Claim · model-written summary
Several separated aromatic biosynthesis isozymes were insensitive to glyphosate.
- Taxon
- mung bean
.jpg?width=60)
Vigna radiatat0 - Treatment
- glyphosatee0
- Outcome
- shikimate dehydrogenase, chorismate mutase, and aromatic aminotransferasee0
- Direction
- insensitivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Multiple isozyme species of shikimate dehydrogenase, chorismate mutase, and aromatic aminotransferase were separated, and these were all insensitive to inhibition by glyphosate.”
t0“mung bean seedings (Vigna radiata [L.] Wilczek)”
Claim · model-written summary
Prephenate and arogenate dehydrogenase activities were not sensitive to inhibition.
- Taxon
- mung beanVigna radiatat0
- Treatment
- glyphosatee0
- Outcome
- activities of prephenate dehydrogenase and arogenate dehydrogenasee0
- Direction
- not sensitivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Multiple isozyme species of shikimate dehydrogenase, chorismate mutase, and aromatic aminotransferase were separated, and these were all insensitive to inhibition by glyphosate. The activities of prephenate dehydrogenase and arogenate dehydrogenase were also not sensitive to inhibition.”
t0“mung bean seedings (Vigna radiata [L.] Wilczek)”
Claim · model-written summary
DAHP synthase-Mn was invulnerable to glyphosate.
- Taxon
- mung beanVigna radiatat0
- Treatment
- glyphosatee0
- Outcome
- DAHP synthase-Mne0
- Direction
- invulnerablee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Whereas DAHP synthase-Mn was invulnerable to glyphosate, greater than 95% inhibition of DAHP synthase-Co was found in the presence of glyphosate.”
t0“mung bean seedings (Vigna radiata [L.] Wilczek)”
Claim · model-written summary
Glyphosate inhibited DAHP synthase-Co by more than 95%.
- Taxon
- mung beanVigna radiatat0
- Treatment
- glyphosatee0
- Outcome
- DAHP synthase-Coe0
- Direction
- inhibitione0
- Value
- greater than 95%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“greater than 95% inhibition of DAHP synthase-Co was found in the presence of glyphosate.”
t0“mung bean seedings (Vigna radiata [L.] Wilczek)”
Claim · model-written summary
Aromatic amino acids showed only a trend toward reversing glyphosate growth inhibition.
- Taxon
- mung beanVigna radiatae0
- Organ / stage
- 7-day seedlingse0
- Treatment
- Aromatic amino acidse0
- Outcome
- growth inhibitione0
- Direction
- reversale0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Aromatic amino acids, singly or in combination, only showed a trend towards reversal of growth inhibition in 7-day seedlings of mung bean.”
The same questions in other papers
glyphosate · molecular: metabolites · Vigna radiata (mung bean)Positive and negative results
1 in the opposite direction
- positive
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.