Copper Flashcards
Is copper supplementation necessary?
No. Trace minerals generally do not need supplementation.
Cuprous and Cupric Copper
+1 reduced (absorbable)
+2 oxidized
Use chaperones so they’re not unnecessarily used within the body.
What can reduce copper or keep it reduced?
Amino acids
Organic acids
Vitamin C
Cytochrome B
Passive diffusion
Only occurs when copper is in excess.
DMT (divalent metal transporter)
Active transporter.
Regulated by iron status. Can transport iron as well.
50% absorbed via DMT
Ctr1 (copper transporter 1)
Regulated based on copper status.
50-80% absorption
Amino acid carriers
Minor copper transporter.
Which vitamins compete with copper absorption?
Zinc
Iron
Calcium
Phytates
Antacids reduce absorption because it lowers pH.
Metallothionine
Zinc regulates metallothionine.
Copper binds better than zinc.
If excess zinc, Cu can’t leave enterocyte because it’s bound to metallothionine
Stored for 2-3 days.
ATP7A
Protein that helps copper leave enterocyte.
Active transport.
Portal blood
Systemic blood
Binds to albumin
Binds to ceruloplasmin. Oxidizes iron. Antioxidant.
90% of copper is bound to ceruloplasmin.
Anemia
Copper deficiency can lead to anemia because most copper is bound to ceruloplasmin which oxidizes iron.
Iron binds to transferrin to be transported to bone marrow to make hemoglobin.
Chaperones
Copper is chaperoned on proteins to prevent oxidation reactions.
Glutathione, Atox1, Cox17
Liver has complete control of copper.
Storage
Transport
Excretion
Storage: Copper stored in metallothionine.
Transport: Ceruloplasmin is produced in liver, binds to copper, released into systemic blood.
Excretion: ATP7B puts copper in bile to be excreted.
Menke’s Disease
Genetic defect not polymorphism.
Cannot make protein ATP7A. Cannot absorb copper.
Children die in infancy.
Copper treatment does not expand lifespan.
Wilson’s Disease
Cannot excrete copper.
Copper toxicity in muscles and liver. Iris.
Chelation. Zinc. Low copper diet.
Sources
RDA: .9 mg
Best: liver, organ meats
Typical: nuts, cashews, potato, whole grains
Bioavailability 50-80%
Increases when Cu status is low
Biochemical Assessment
Serum copper (static)
Serum ceruloplasmin activity (functional)
Functions
Coenzyme. Enzymes that need a reduced metal.
Ceruloplasmin: antioxidant, oxidizes iron (ferroxidase)
Cytochrome c Oxidase: used in ETC to transport e-
Deficiency
At risk if using antacids and zinc supplements (40mg/d).
Hypochromic anemia: most Cu is bound to ceruloplasmin which transfers Fe to transferrin to bone marrow to make blood
Leukopenia: impaired immune function
Hypopigmentation: depigmentation of hair
Zinc toxicity makes copper deficiency because metallothionine is upregulated and Cu binds to it.
Iron toxicity makes Cu deficiency because DMT1 is down regulated which absorbs 50% of Cu
Toxicity
10 mg/day
Nausea, vomiting, diarrhea, kidney and liver damage.
Kayser-Fleischer Ring
Wilson’s Disease
Copper toxicity. Ring around the eye.
Cytochrome c Oxidase
Last step in ETC.
Contain 3 Cu atoms on 2 subunits:
The first subunit contains 2 Cu atoms that receive e from cytochrome c.
Transfer to second subunit to reduce oxygen.
Creates ATP.
Nutrient interactions
Iron: low Cu that leads to low ceruloplasmin which traps iron in the cells. Secondary iron deficiency anemia.
Molybdenum: enhances copper excretion.
