Characterization and possible redox regulation of the purified calmodulin‐dependent NAD<b><sup>+</sup></b> kinase from <i>Lycopersicon pimpinellifolium</i>
Bibliographic record
Abstract
ABSTRACT The soluble and calmodulin (CaM)‐dependent NAD + kinase from Lycopersicon pimpinellifolium was previously shown to be largely inactivated in isolated cells exposed to a short‐term NaCl stress (Delumeau, Morère‐Le Paven, Montrichard, Laval‐Martin (2000) Plant Cell & Environment 23, 329–336). Nevertheless, the activity could be restored by adding a high dithiothreitol concentration to the protein extract, suggesting that the salt stress triggers an oxidation of the enzyme which leads to its inactivation. It was then interesting to investigate the effect of thiol‐modifying reagents and disulphide reductants on the activity of L. pimpinellifolium NAD + kinase. A three‐step purification procedure was then established and allowed isolation of the enzyme which exists under two forms: a monomer and a dimer of a 56 kDa subunit, characterized, respectively, by pIs of 6·8 and 7·1. Isolated NAD + kinase had a high affinity for CaM, half saturation being obtained for 7 ng mL − 1 bovine CaM. The activity of NAD + kinase was strongly inhibited by thiol‐modifying reagents and oxidized glutathione. NAD + kinase was also found to be air‐inactivated, the residual activity being stimulated by disulphide reductants. The most efficient of them is reduced thioredoxin from Escherichia coli which induced a five‐fold increase in activity and restored 80% of the initial activity. These results which can be related to those previously observed in vivo suggest that the activity of the L. pimpinellifolium NAD + kinase, besides its dependence on CaM, is also dependent on the reduction state of the protein which could be regulated by the thioredoxin h /NADP‐thioredoxin reductase system.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".