Copper !

Copper powers enzymes that use oxygen, build collagen and melanin and move iron; two genetic diseases show its lack and its excess.

Updated 2026-11-01

Key facts

Copper enzymes: cytochrome c oxidase (complex IV), lysyl oxidase (collagen and elastin cross-links), tyrosinase (melanin), dopamine β-hydroxylase, superoxide dismutase (Cu/Zn), ceruloplasmin.
ATP7A moves copper out of the gut into blood: its failure causes Menkes disease (deficiency).
ATP7B loads it onto ceruloplasmin and excretes it in bile: its failure causes Wilson disease (accumulation).
Ceruloplasmin carries almost all plasma copper and oxidises iron for transferrin.

Sources: organ meats (liver), shellfish, nuts, seeds, cocoa, legumes.
Absorption: in the proximal small intestine via CTR1; ATP7A pumps it to the blood side; it reaches the liver bound to albumin.
In the hepatocyte, ATP7B incorporates it into ceruloplasmin and sends the surplus into bile, the only major route of elimination.
Acquired deficiency: excess zinc, bariatric surgery or gastrectomy, malabsorption, copper-free parenteral nutrition. It causes anaemia (failed hephaestin and ceruloplasmin), neutropenia and a myelopathy that resembles B12 deficiency.
Excess: Wilson disease (liver, brain, cornea), acute poisoning by copper salts (vomiting, haemolysis, liver necrosis).
Lab: serum copper, ceruloplasmin, 24-hour urine copper; in Wilson disease, liver biopsy copper.

Copper deficiency can be mistaken for myelodysplastic syndrome or B12 deficiency (anaemia, neutropenia, ataxia).
Wilson disease is suspected in a young person with unexplained hepatitis or cirrhosis, tremor or psychiatric change, and Kayser-Fleischer rings.
Menkes disease causes kinky, brittle hair, hypotonia and seizures in a baby boy.

Think of the answer, then tap the question to see it.

Which copper enzyme forms collagen cross-links?

Lysyl oxidase; without it collagen and elastin are weak (tortuous vessels and aneurysms in Menkes).

What is the difference between ATP7A and ATP7B?

ATP7A exports copper from enterocytes to blood (failure: Menkes). ATP7B excretes it from hepatocytes into bile (failure: Wilson).

Why does copper deficiency cause anaemia?

Hephaestin and ceruloplasmin, both copper enzymes, oxidise iron to load it onto transferrin; without them iron is trapped.

Why is ceruloplasmin low in Wilson disease?

Without ATP7B copper is not built into ceruloplasmin; the empty protein is degraded quickly.

Educational information, not medical advice. For any symptom, see a health professional.

Sources: Copper in diet: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); ATP7A gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); ATP7B gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); Ceruloplasmin Test: MedlinePlus Medical Test (MedlinePlus, US National Library of Medicine, 2026); ATP7B: Copper-transporting ATPase 2 (human) (UniProt, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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Representative model, for educational purposes only.