Copper metalloproteomics: using immobilized metal affinity chromatography, two-dimensional gel electrophoresis and mass spectrometry to search for hepatocellular proteins with copper-binding ability
Bibliographic record
Abstract
Copper is an essential trace element that participates in diverse biochemical reactions in all aerobic organisms. We have outlined the make up of the human copper metalloproteome. HepG2 cytosolic and microsomal fractions were applied to a copper(II)-loaded immobilized metal affinity chromatography (IMAC) column. Bound proteins were eluted with 50 mM EDTA, separated by 2D-gel electrophoresis and identified by MALDI-QqTOF mass spectrometry. We identified 48 cytosolic proteins and 19 microsomal proteins with copper-binding ability. To our knowledge, this is the first effort to describe the composition of the copper metalloproteome. Members of the 2-Cys family of peroxiredoxins (Prxs) were identified in this study but were not previously known to bind copper. Results presented here indicate that Prx3, a 25 kDa mitochondrial protein with peroxidase activity, converts Cu(II) to Cu(I) and binds Cu(I) with a stoichiometry of 2 mol Cu(I) per monomer of protein. The physiological relevance of Prx3 copper-binding is unclear.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".