Bibliographic record
Abstract
Abstract A single gene product has been identified as responsible for the two catalytic activities, xanthine dehydrogenase, XDH (EC 1.1.1.204), and xanthine oxidase, XO (EC 1.2.3.2). Synthesized as XDH (ultimate electron acceptor NAD + ), the protein can be converted to XO (ultimate electron acceptor oxygen) either reversibly by oxidation of cysteine residues or irreversibly by proteolysis. Xanthine oxidoreductase (XOR) is a ubiquitous enzyme; its physiological role is the oxidation of hypoxanthine to xanthine and further to uric acid, although in vitro the enzyme's specificity is rather broad, accepting a large number of purines, pteridines, and aldehydes as substrates. XOR, in contrast to most other hydroxylases, incorporates water‐derived oxygen into its substrate. The electrons are transferred from xanthine to a Mopterin center and from there via two Fe 2 –S 2 clusters and FAD to NAD + or oxygen, respectively. The enzyme is the target of the antigout drug allopurinol; it is involved in hyperuricemia and xanthinuria and postulated to participate in postischemic reperfusion injury. Crystal structures have been determined for native and mutant XDHs and XOs from man, cow, rat, and Rhodobacter capsulatus . The conformational changes linked to the dehydrogenase/oxidase transition have been identified and interpreted. A structure‐based explanation for the catalytic mechanism is emerging.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 0.001 |
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".