• Haemoglobin is found in red blood cells
  • The haemoglobin molecule is a tetramer consisting of 4 polypeptide chains, known as globins, which are usually:
  • 2 alpha chains that are each 141 amino acids long
  • 2 beta chains that are each 146 amino acids long
  • Attached to each chain is an iron-containing molecule known as haem

The image above shows the structure
of haemoglobin. The coiled structures
are the polypeptide chains, the silver balls
are the iron molecules and the gold
surrounding the iron represents haem.


The image above shows the strucure
of haem (iron is shown in red).

Both images reproduced from Haemoglobin, BioNet
Permission granted by Dr J M Basford,
University of Cardiff

  • Oxygen is transported in combination with the iron molecule of the haem group (this is an oxygenation reaction, not an oxidation)