Question: What is haemaglobin?

Xiaohan Li answered on 12 Mar 2020:

Hi,

Thank you for the question! Haemoglobin is the protein which carries oxygen in the red blood cells and transfers oxygen to our cells. It’s red color comes from the color of haem, a small coordination complex with an iron centre and also where the oxygen binds. Each haemoglobin consists of 4 subunits, and each can carry one oxygen molecule. These subunits can “talk” to each other: binding of one oxygen molecule in one subunit will make it easier for oxygen to bind to other subunits. And this creates what we call “cooperativity” of the binding.