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C9. Metal ions in biological systems

C9. Metal ions in biological systems. April 4th. General. Many metal ions have role in biological processes of the body The ions have different physical and chemical properties Charge density Complex formation Oxidation states Minerals in food. Ion Ca 2+ Mg 2+ Fe 2+ Cu 2+ Zn 2+

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C9. Metal ions in biological systems

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  1. C9. Metal ions in biological systems April 4th

  2. General • Many metal ions have role in biological processes of the body • The ions have different physical and chemical properties • Charge density • Complex formation • Oxidation states • Minerals in food

  3. Ion Ca2+ Mg2+ Fe2+ Cu2+ Zn2+ Co3+ Na+ K+ Role: 1.5-2% of body mass, bones, teeth Bones and teeth, intracellular activity Hemoglobin, O2 transfer Cofactor in enzymes Cofactor in enzymes,growth, healing In vitamin B12 Water balance, nerve impulses, fluids inside and outside cells The most important ions

  4. ATP = adenosine triphosphate • A nucleotide (ribose sugar, adenine base and three phosphate groups) • Energy currency of the cell, providing the energy for most of the energy-consuming activities • It regulates many biochemical pathways

  5. ATP as energy source • The exothermic reaction is (hydrolysis): • ATP + H2O → ADP + Pi + E • ADP is adenosine diphosphate • Pi is phosphate group, HOPO32- • Reversible process

  6. Na+/K+ pump • Found in membranes of cells. • Produces electrical and chemical gradient across a cell membrane. • It plays a very important role in nerve cell membranes. • Transmission of nerve impulses. • Channel = tunnel-like trans membrane protein: Na+-K+ ATPase • K+ inside a cell • Na+ outside a cell • Cell surface membranes pump Na+ ions out of cell and K+ in.

  7. Na+/K+ pump • The pump requires energy: • ATP + H2O → ADP + Pi + E • With 1 mol ATP: • 3 mol of Na+ and 2 mol of K+ pumped out/in • Animation

  8. Electron transport • Energy from food is released through many redox reactions (mitochondria) • Transition metals have many oxidation states. • => They can carry charges. • Cytochromes are oxidizing enzymes. • Contain copper or iron as cofactors. • Cu2+ + e– ↔ Cu+; Fe3+ + e– ↔ Fe2+ • Animation

  9. Cu in cytochrome oxidase

  10. Hemoglobin as oxygen carrier • In each hemoglobin molecule there are four heme groups • Heme = Fe2+ surrounded by phorphyrin group, four N act as ligands. • As O2 carrier: O2 binds to Fe2+ as a ligand • Reversible process • CO and CN– bind irreversible to Fe2+

  11. Hemoglobin Binding of O2 alters the structure

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