Question

What type of compound is hemoglobin?

Answer 1

A porphyrin-containing metalloprotein.

Explanation:

At a simple level, we can say that hemoglobin (a.k.a. haemoglobin) is a metalloprotein. Its molecular mass is about `64000`, which gives you some idea as to the complexity of the molecule.

One molecule of hemoglobin contains `4` heme groups, each of which contains a single atom of iron. The iron atom is directly bound to `5` surrounding nitrogen atons in a porphyrin ring. Note that it is not directly bound to a carbon atom, so heme and hemoglobin are not counted as organometallic.

Apart from these `4` iron atoms, the rest of the hemoglobin molecule is organic, containing several protein chains.

It is interesting to compare hemoglobin with chlorophyll, a somewhat simpler metalloprotein that has magnesium instead of iron.