Myoglobin vs Haemoglobin

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Myoglobin and hemoglobin differ in structure and function:

• Structure:

  • Myoglobin: single monomer (one polypeptide chain)

  • Hemoglobin: tetramer (four subunits, quaternary structure)

• Binding:

  • Myoglobin binds O₂ (with some ability to bind carbon monoxide)

  • Hemoglobin transports O₂ and other molecules

• Location:

  • Myoglobin is found in muscle cells

  • Hemoglobin is present in red blood cells, circulating throughout the body

• Function:

  • Myoglobin serves as oxygen storage and supply to muscles

  • Hemoglobin transports oxygen across the body

• Oxygen Binding:

  • Myoglobin binds O₂ strongly at low partial pressures

  • Hemoglobin binds and releases O₂ strongly, efficient in varying oxygen conditions

• Concentration:

  • High concentration of hemoglobin in red blood cells, low concentration of myoglobin

• Saturation:

  • Myoglobin is 50% saturated at 1 torr, reaches 100% at 100 torr

  • Hemoglobin also reaches 100% saturation at 100 torr, crucial for gas exchange in the lungs.