Abstract
The effects of externally induced metabolic perturbations are often studied through changes of the enzyme activity patterns in crude plant extracts. From glutamate dehydrogenase (GDH) it is reported that environmental changes not only influence the amount of the enzymatic activity, but also the ratio of the aminating to the deaminating activities (NADH/NAD+ ratio). Using crude cell extracts of suspension cultures of wheat (Triticum aestivum L. cv. Heines Koga II) we find evidence that the pretreatment of the homogenate directly influences this ratio. Dialysis of these crude cell extracts resulted in a 70% loss of the NAD+ activity, while the NADH activity remained unchanged. The deaminating activity in the dialysed extract could be completely restored upon addition of a dialysable factor which was identified to be malate. The interference of malate with the glutamate dehydrogenase reaction is caused through the action of malate dehydrogenase and glutamate oxaloacetate transaminase which are both present in high activities in the extracts. Only in exhaustively dialysed cell extracts can the proper deaminating GDH activity be determined. The results are discussed in the light of the controversial reports on the variable ratio of the NADH/NAD+ activity of GDH.
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Claims 6
Claim · model-written summary
Pretreatment of the homogenate of wheat suspension culture extracts directly influences the NADH/NAD+ activity ratio of glutamate dehydrogenase.
- Taxon
- wheat
Triticum aestivume0 - Material
- Heines Koga IIe0
- Treatment
- pretreatment of the homogenatee0
- Outcome
- this ratioe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Using crude cell extracts of suspension cultures of wheat (Triticum aestivum L. cv. Heines Koga II) we find evidence that the pretreatment of the homogenate directly influences this ratio”
Claim · model-written summary
Dialysis of crude wheat cell extracts caused a 70% loss of NAD+ activity.
- Taxon
- wheatTriticum aestivume1
- Treatment
- Dialysis of these crude cell extractse0
- Outcome
- NAD+ activitye0
- Direction
- losse0
- Value
- 70%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“suspension cultures of wheat”
e0“Dialysis of these crude cell extracts resulted in a 70% loss of the NAD+ activity”
Claim · model-written summary
Dialysis of crude wheat cell extracts left NADH activity unchanged.
- Taxon
- wheatTriticum aestivume1
- Treatment
- Dialysis of these crude cell extractse0
- Outcome
- NADH activitye0
- Direction
- unchangede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“suspension cultures of wheat”
e0“Dialysis of these crude cell extracts resulted in a 70% loss of the NAD+ activity, while the NADH activity remained unchanged”
Claim · model-written summary
Deaminating activity in the dialysed extract was completely restored by adding a dialysable factor identified as malate.
- Taxon
- wheatTriticum aestivume1
- Treatment
- addition of a dialysable factor which was identified to be malatee0
- Outcome
- deaminating activitye0
- Direction
- restorede0
- Comparator
- dialysed extracte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“suspension cultures of wheat”
e0“The deaminating activity in the dialysed extract could be completely restored upon addition of a dialysable factor which was identified to be malate”
Claim · model-written summary
Malate interference with the glutamate dehydrogenase reaction is caused by malate dehydrogenase and glutamate oxaloacetate transaminase, both highly active in the extracts.
- Taxon
- wheatTriticum aestivume1
- Gene
- malate dehydrogenase and glutamate oxaloacetate transaminasee0
- Outcome
- interference of malate with the glutamate dehydrogenase reactione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“suspension cultures of wheat”
e0“The interference of malate with the glutamate dehydrogenase reaction is caused through the action of malate dehydrogenase and glutamate oxaloacetate transaminase which are both present in high activities in the extracts”
Claim · model-written summary
Proper deaminating GDH activity can be determined only in exhaustively dialysed wheat cell extracts.
- Taxon
- wheatTriticum aestivume1
- Outcome
- proper deaminating GDH activity be determinede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“suspension cultures of wheat”
e0“Only in exhaustively dialysed cell extracts can the proper deaminating GDH activity be determined”
The same questions in other papers
botanical · molecular: metabolites · Triticum aestivum (wheat)Positive and negative results
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