The effect of methyl acceptors on betaine metabolism and the fate of betaine‐derived methyl groups in rat hepatocytes
Bibliographic record
Abstract
Despite well articulated metabolic pathways, little is known of how betaine metabolism is regulated or what controls its catabolism and the fate of the three methyl groups of the trimethylamine moiety. Using rat primary hepatocytes we investigated the metabolism of 3‐[ 14 CH 3 ]‐labeled betaine. This study, for the first time, explores the fate of the betaine methyl groups in isolated liver cells. Approximately 50% of the metabolised methyl groups are found in an acid soluble fraction that, based on ion exchange chromatography, is consistent with the products of betaine:homocysteine methyltransferase, methionine and dimethylglycine. The remaining methyl groups were metabolised to volatile compounds, likely CO 2 or formate. Betaine concentration did not affect the relative proportion of label found in the volatile fraction. Total product formation from betaine has an apparent K m of 0.41 mM, somewhat above arterial plasma values (∼ 0.1–0.2 mM). The addition of homocysteine as a methyl acceptor had no effect on betaine metabolism; however, glycine (methyl acceptor and precursor of serine) markedly decreases the relative amount of volatile product formation. This work was funded by CIHR.
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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 | 0.000 |
| 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) | 0.001 | 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".