Novel substrates for efficient enzymatic transglycosylation by <i>Bacillus circulans</i>
Bibliographic record
Abstract
To develop transglycosylation for efficient preparation of N-acetyllactosamine (Galβ(1[Formula: see text]4)GlcNAc, LacNAc), β-galactosidase mediated transglycosylation using novel substrates Bacillus Circulans was explored. To make transglycosylation entropically favorable over hydrolysis, donor (lactose or galactose) and acceptor (N-acetyl glucosamine, GlcNAc) components were connected to a single molecule. For that purpose, 1,2- and 1,3-benzene dimethanol and 2-hydroxy-5-nitro- and 5-hydroxy-2-nitro-benzyl alcohol were screened as linkers and enzymatic transglycosylation was examined under several conditions. In the case of 2-hydroxy-5-nitro-benzyl connected substrate 40, an indication of the occurrence of intramolecular transglycosylation was observed, and the desired product (58) was obtained in 26% isolated yield. The same reaction in the presence of CMP sialic acid and α-(2[Formula: see text]6)-sialyltransferase gave sialyl LacNAc 87 in one pot in 39% isolated yield. Additionally, the effect of the C-2 substituent of the acceptor component was briefly examined using substrates containing NHAlloc (72), NHTroc (73), and N3 (74) groups. Although the occurrence of intramolecular transglycosylation was not clear in these cases, disaccharides 8183 were obtained in reasonable yields.Key words: galactosidase, intramolecular transglycosylation, N-acetyllactosamine, sialyltransferase.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".