Bibliographic record
Abstract
Introduction Recent activity in this laboratory has involved the electrochemistry of amino acids such as L-cysteine and L-histidine in aqueous buffers (1-4). The effect of zinc ions, which are involved in determining the structures of “zinc finger” proteins (5), on the electrochemistry of amino acids has also been investigated. The present work has extended these studies to L-tryptophan and some of its derivatives. Experimental MOPS (3-(N-morpholino)propanesulfonic acid) was obtained from Sigma-Aldrich Corporation, and L-tryptophan was obtained from Nutritional Biochemical Systems. Electrochemical experiments were carried out under nitrogen using a Gamry Instruments Interface 1000 potentiostat and Gamry Framework software. Working electrodes were obtained from BASi (Glassy carbon, 3.0 mm diameter; platinum 1.6 mm) and eDAQ (gold, 1.0 mm diameter). Potentials were measured with respect to a silver/silver chloride saturated KCl reference electrode (eDAQ). Results and Discussion Electrochemical studies of L-tryptophan have been carried out in pH 7.4 phosphate buffer, and we have found that L-tryptophan undergoes oxidation more easily than does L-histidine (4). Complexation studies of Zn(II) by L-tryptophan in pH 7.4 MOPS buffer have shown that the extent of complexation is generally similar to that of L-histidine (4). Similar experiments were also carried out on 5-fluoro-tryptophan and 6-fluoro-tryptophan, revealing that they underwent oxidation at somewhat more positive potentials than does L-tryptophan. This observation reflects the electron-withdrawing effect of the fluorine atom. Despite this positive potential shift, the fluorinated tryptophans were found to effectively complex zinc(II) in pH 7.4 MOPS buffer. Finally, initial experiments in the voltammetric behavior of L-tryptophan in the very polar solvent formamide have been initiated. References 1. G. T. Cheek and M. A. Worosz, ECS Transactions, 2016, 72(27), 1-8. 2. M. Y. Doan, M. A. Worosz, and G.T. Cheek, ECS Transactions, 2017, 77(11), 1537-1544. 3. G. T. Cheek, M. A. Worosz, M. Y. Doan, and D. C. Clark, ECS Transactions 2017 80(10), 1159-1166. 4. D.C. Clark and G.T. Cheek, ECS Transactions, 2018, 85(13), 1123-1131. 5. C.K. Mathews, K.E. Van Holde, D.R. Appling, and S. J. Anthony-Cahill, Biochemistry, 4th Edition, Pearson Canada, Toronto, 2013.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".