Specific starch digestion of maize alpha‐limit dextrins by recombinant mucosal glucosidase enzymes
Bibliographic record
Abstract
Starch digestion requires two luminal enzymes, salivary and pancreatic alpha‐amylase (AMY), and four small intestinal mucosal enzyme activities from the N‐ and C‐terminals of maltase‐glucoamylase (MGAM) and sucrose‐isomaltase (SI) complexes. AMY is not a requirement for starch digestion to glucose but dramatically amplifies α‐glucogenesis by producing α‐limit dextrins (LDx) as favored substrates for the mucosal enzymes. Aim to study substrate specificity of α‐glucogenesis by four recombinant MGAM and SI subunits. Methods Recombinant α‐glucosidase domains were produced in drosophila (N‐) or baculovirus (C‐) cell lines and purified by histags. LDx was produced with AMY from normal maize and three mutant cultivars with different amylopectin structures: normal, waxy, ae waxy and du waxy. Glucose released in vitro was measured by GOPOD. Results N‐MGAM subunit releases glucose from shortest linear oligomers while the other three subunits digest longer chains or branched molecules. Conclusions This is the first time that the individual α‐glucogenic activities of all four mucosal enzyme subunits have been tested. The individual α‐glucosidase subunits had different activities for each cultivar LDx substrate and selective affinities for LDx from different cultivars. Combinations of α‐glucosidase subunits thus provide a broader spectrum of α‐glucogenic activities from structurally varied starch LDx.
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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) | 0.000 | 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".