Purification and characterization of a small copper carrier found in mammalian blood plasma and in the urine of mice and dogs with copper overload
Bibliographic record
Abstract
We recently discovered a small copper carrier (SCC), which in most mammals is mainly bound to larger proteins and can be released by EDTA. It normally accounts for at least 10% of total plasma copper, and more than half the total in Atp7b−/− mice and some Labrador retrievers with copper overload, where it circulates in the “free” form and appears in the urine. This suggests SCC is an alternative means of excreting copper when biliary excretion is inhibited. To begin to isolate and characterize SCC, blood plasma of human volunteers (permitted by the university IRB), pigs, cows, sheep and Labrador retriever dogs were analyzed for their quantities or free and protein‐bound SCC, using 10 and 3kDa ultrafiltration and size exclusion chromatography (SEC) with Superdex 200 and peptide FPLC. By MALDI‐TOF, the main component identified as potentially SCC consistently had a mass of 1329.5 Da (not including Cu), identical to that reported for urinary SCC from Atp7b−/− mice. It eluted between vitamin B12 and NADH in small pore SEC and not with Cu‐EDTA, which aggregated. Two amino acids were identified; a third was blocked by sulfate or phosphate. However, solution NMR indicated the samples were not pure. Preliminary data suggested phenyl HIC and anion exchange might be useful purification steps. Plasma from the pig had the highest levels of total SCC and more than 10% in the “free form”. So it was chosen to identify the best steps for large scale SCC purification.
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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 | 0.001 | 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) | 0.001 | 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".