The number of Fe++ atoms in one Hb molecule

Hemoglobin is a globular molecule made up of four subunits. Each subunit contains a heme moiety conjugated to a polypeptide. Heme is an iron-containing porphyrin derivative. So, hemoglobin = 4 globins + 4 heme groups Since each heme molecule contains an iron, so total iron atoms present in hemoglobin are 4 in number. 70% of the iron in the body is in hemoglobin, 3% in myoglobin, and the rest in ferritin, which is present not only in enterocytes, but also in many other cells.