Respiratory pigments of human being is haemoglobin :
Haemoglobin : It is a red coloured pigment formed of iron and protein. Haemoglobin is a red coloured iron containing pigment present in the RBCs. O2 binds with haemoglobin in a reversible manner to and form oxyhaemoglobin. One haemoglobin molecule can carry a maximum of four molecules of O2.