Characterization of the Asiatic Acid Glucosyltransferase, UGT73AH1, Involved in Asiaticoside Biosynthesis in Centella asiatica (L.) Urban
Bibliographic record
Abstract
Centella asiatica (L.) Urban contains two ursane-type triterpene saponins, asiaticoside and madecassoside, as major secondary metabolites. In order to select candidate genes encoding UDP-glucosyltransferases (UGTs) involved in asiaticoside biosynthesis, we performed transcriptomic analysis of leaves elicited by methyl jasmonate (MeJA). Among the unigenes, 120 isotigs and 13 singletons of unique sequences were annotated as UGTs, including 37 putative full-length cDNAs, and 15 of the putative UGT genes were named according to the UGT committee nomenclature protocols. One of them, UGT73AH1, was characterized by heterologous expression in Escherichia coli BL21 (DE3) cells. After induction with IPTG, a total protein extract was assayed with UDP-glucose and asiatic acid. UPLC-QTOF/MS analysis showed that UGT73AH1 catalyzes the glycosylation of asiatic acid to its monoglucoside. It remains unclear whether glycosylation occurs on the triterpene C-2α, C-3β, C-23, or C-28 position. However, it is very likely that UGT73AH1 glucosylates the C-28 position, because only C-28 bears a glucose moiety in the final pathway product of asiatic acid, while C-2α, C-3β, and C-23 remain un-conjugated.
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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 | 0.001 |
| 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) | 0.000 | 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".