Method for identifying the phosphorylation site of Maize Starch Synthase I
Bibliographic record
Abstract
Multiple forms of starch synthases (EC 2.4.1.21) are critical for the synthesis of starch in higher plants. These enzymes catalyze the extension of linear glucan chains by the transfer of glucose from the nucleotide sugar ADPglucose. Recombinant maize starch synthase I (rSSI) was purified from Escherichia coli in order to study the regulation of this enzyme by protein phosphorylation. The rSSI was phosphorylated in vitro by incubation with [γ 32P]-ATP and maize amyloplast lysates, which were used as a source of protein kinase. Maximal phosphorylation of rSSI was achieved within 20 minutes, and there was no noticeable change in the amount of phosphorylation beyond this time. Phosphoamino acid analysis of rSSI indicated phosphorylation of one or more serine residues. In order to purify and identify the phosphopeptides, phosphorylated rSSI was digested with trypsin to yield smaller peptides, which were then concentrated using Immobilized Metal Affinity Chromatography (IMAC). Potential phosphopeptides eluting from the IMAC column were purified and putatively identified using reversed phase (C18 column) High Pressure Liquid Chromatography (HPLC). They were then analyzed by mass spectrometry using Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) which yielded the mass of potential phosphopeptides.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.008 | 0.006 |
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".