Myoglobin

• The Graph:

  A) Myoglobin

  B) Foetal Haemoglobin

  C) Normal Haemoglobin

  
• Red pigment found in muscles; it has a single polypeptide chain and one haem group; combines with only one oxygen molecule (oxymyoglobin); combines reversibly with O_2, but has a greater affinity for O_2 than Hb, oxymyoglobin is very stable, unless the partial pressure is very low
• It is an oxygen store/reserve to be used only if there is great oxygen demand; like during very strenuous exercise when demand is greater than can be supplied by blood and Hb