Copper, Cu

Overview of Copper

Basic Characteristics Copper is a chemical element from the IB group of the periodic table. With a reddish, shiny appearance, copper is heavier than iron. Its symbol is Cu, with the atomic number 29 and atomic mass of 63.55. Natural copper comprises two stable isotopes: 63 Cu (69.1%) and 65 Cu (30.9%).

Copper in the Human Body

The human body contains about 110 mg of copper:

• Liver: ~10 mg
• Brain: ~9 mg
• Blood, spleen, and bone marrow: ~46 mg
• Muscle tissue: ~26 mg

Most of the body’s copper binds to proteins. Due to its ability to exist in monovalent and divalent forms, copper plays a role in oxidation-reduction reactions. It acts as an acceptor of electron pairs in biological reactions.

Role in Enzymes and Proteins

Copper is an essential part of various enzymes such as cytochrome oxidase, tyrosinase, ascorbinase, and superoxide dismutase. Copper-containing proteins typically reside on the cell surface or membranes, although superoxide dismutase is found in the cytoplasm. These proteins are characterized by a β-sheet structure.

Dietary Sources and Absorption

Copper is abundant in legumes, grains, mushrooms, chocolate, seeds, nuts, liver, and seafood. The recommended daily intake for adults is 1.5-3 mg. Copper absorbed from the digestive tract binds to plasma albumins, enters the liver, and binds to ceruloplasmin—a glycoprotein composed of 6-7% carbohydrates, capable of binding six copper atoms. This complex then enters the circulatory system and reaches peripheral tissues. Excess copper is excreted with bile acids.

Health Implications

Essential for Enzyme Activity: Copper is necessary for the activity of certain crucial enzymes.
Potential Hazards: Free or improperly bound copper can catalyze the production of free oxygen radicals.
Copper Deficiency: Leads to functional and biochemical changes, weakening the immune system and causing alterations in electrocardiograms, connective tissue of blood vessel walls, heart hypertrophy, fatty acid and noradrenaline metabolism, glucose intolerance, hypotension, hypercholesterolemia, and structural changes in the heart.

Copper Homeostasis Disorders

Menkes Syndrome (Copper Deficiency):

• Results from mutations in copper ATPase 7A.
• Characterized by low copper and ceruloplasmin in the serum, liver, and brain.
• Excess copper accumulates in the intestinal mucosa, muscles, spleen, and kidneys.
• Symptoms include “kinky” hair and progressive brain degeneration.
• Patients usually die within three years.

Wilson’s Syndrome (Copper Excess):

• Typically diagnosed after age 30.
• Results from mutations in copper ATPase 7B.
• Characterized by low serum ceruloplasmin; copper accumulates in the brain and liver due to impaired excretion with bile acids.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė