Bibliographic record
Abstract
Starch is widely used in food and non-food sectors.Its biosynthesis is known to involve at least four groups of committed enzymes: ADP-glucose pyrophosphorylase, starch synthases (SS), starch branching enzymes (SBE), and debranching enzymes (DBE).Plastidial starch phosphorylase (SP) is also suggested to be involved in starch biosynthesis.Significant proportions of the starch biosynthetic enzymes, particularly SSI, SSIIa, and SBEIIb are bound to starch granules in maize.In this thesis, biochemical studies on protein-protein interactions between key enzymes of the starch biosynthetic pathway in wheat and maize endosperms, identify a potentially important mechanism of regulating starch biosynthesis by formation of phosphorylation-dependent multi-enzyme complexes between isoforms of starch synthases and branching enzymes.Furthermore, studies on a well-characterized maize mutant lacking the dominant branching enzyme activity, SBEIIb, amylose extender (ae -), demonstrated distinct patterns of protein-protein interactions compared with wild-type, suggesting functional complementation for the loss of SBEIIb in protein complexes by SBEI, SBEIIa and SP.Co-immunoprecipitation using peptide-specific antibodies showed that in amyloplasts from normal maize endosperm, protein-protein interactions involving SSI, SSIIa, and SBEIIb could be detected.By contrast, in ae -amyloplasts, SSI and SSIIa were shown to interact with SBEI, SBEIIa and SP.All interactions in normal maize were strongly enhanced by ATP, and reduced by the addition of alkaline phosphatase, indicating a role for protein phosphorylation in assembly.All the protein-protein interactions observed in wildtype and the ae -mutant occur during the grain-filling stage of endosperm development.Interactions were also reconstituted in vitro using recombinant forms of SSs and SBEs.This study proposes that during amylopectin biosynthesis in maize amyloplasts, SSI and SSIIa form the core of a phosphorylation-dependent glucan-synthesizing protein complex which, in wildtype endosperm, recruits SBEIIb, but when SBEIIb is absent (ae -), recruits SBEI, SBEIIa and SP.These differences in protein complexes are mirrored in the complement of starch synthesizing enzymes detected in starch granules of each genotype, reinforcing the hypothesis that the complexes play a functional role in starch biosynthesis.i
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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) | 0.002 | 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".