copper study guide

What is the deficiency disease of copper?

Copper deficiency or Menkes disease (ATP7A mutation).

What happens during copper deficiency?

Iron becomes trapped in enterocytes, less iron reaches tissues, anemia develops.

What are the symptoms of Menkes disease?

Brittle or kinky hair, developmental delay, neurological problems, copper buildup in intestinal cells, poor copper delivery to tissues.

What is copper toxicity called?

Wilson's disease (ATP7B mutation).

What happens during Wilson's disease?

Copper cannot be excreted into bile, so copper accumulates in the liver and other tissues. golden-brown or copper-colored rings around the outer edge of the eyes

Copper Absorption Facts

Where is copper absorbed?

• Mainly the small intestine.

How much copper is absorbed?

• About 50–80% of dietary copper.

What form is copper in before absorption?

• Mostly Cu²⁺ (cupric copper).

What form is absorbed?

• Cu⁺ (cuprous copper).

What is required for absorption?

• Cu²⁺ must be reduced to Cu⁺ by reductases before absorption.

Copper Absorption Pathway

Food copper
↓
Cu²⁺
↓
Reductases
↓
Cu⁺
↓
Ctr1
(main uptake transporter)
↓
Enterocyte
↓
Copper chaperones
↓
Atox1
↓
ATP7A
↓
Blood
↓
Liver
↓
ATP7B
↓
Ceruloplasmin
(major circulating copper protein)

Requirements for Absorption

• Copper must be reduced from Cu²⁺ to Cu⁺.

• Ctr1 transports Cu⁺, not Cu²⁺.

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Enhancers

• Acidic pH

• Histidine

• Cysteine

• Organic acids

Inhibitors

• High zinc

• High iron

• High calcium

• Phytates

• Alkaline pH (antacids)

High-yield summary for abs

Into the enterocyte

• Ctr1 (main)

• DMT1 (minor)

Inside the enterocyte

• Copper chaperones

• Atox1

Out of the enterocyte

• ATP7A

In the liver

• ATP7B

In the blood

• Ceruloplasmin

circulating form of copper

Ceruloplasmin

storage form of copper

Metallothionein

functions of copper

interaction between zinc and copper

High zinc intake
↓
↑ Metallothionein synthesis in the enterocyte
↓
Metallothionein binds copper more strongly than zinc
↓
Copper becomes trapped in the enterocyte
↓
When the enterocyte is naturally shed, the copper is lost in the feces
↓
↓ Copper absorption
↓
Copper deficiency

copper deficiency causes anemia

true

high zinc

copper deficiency

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