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## Hemoglobin Molecule - Hb molecule is composed of four subunits, each containing heme and globin - Heme contains four iron atoms at Ferrous (Fe+2) state - One heme molecule binds one molecule of O2. Thus one Hb molecule binds four molecules of O2. - The globin in each Hb molecule consists of four...

## Hemoglobin Molecule - Hb molecule is composed of four subunits, each containing heme and globin - Heme contains four iron atoms at Ferrous (Fe+2) state - One heme molecule binds one molecule of O2. Thus one Hb molecule binds four molecules of O2. - The globin in each Hb molecule consists of four polypeptide chains which determine the type of Hb formed. - Adult hemoglobin (HbA) is composed of two alpha and two beta chains. Minor part of adult Hb (HbA2) is composed of two alpha and two delta chains. Fetal Hb (HbF) is composed of two alpha and two gamma chains. - In embryonic life, other Hbs are present as Hb Portland, Gower I and Gower II ## Hemoglobinopathies Conditions caused by qualitative structural abnormalities of the globin polypeptide chains that result from alteration of the DNA genetic code for those chains (e.g. sickle cell anemia, Hb C disease) ### Hemoglobinopathies - **Qualitative** - Abnormal Hb - Cause: point mutation (single nucleotide alteration) - **Quantitative** - Thalassemia (Hb quantity less than normal) - Cause: point or deletional mutation ### Hemoglobin A - Alpha Thalassemia - Beta Thalassemia - Sickle Cell Disease ### Thalassemias Conditions caused by quantitative abnormality in globin chain (i.e., reduced or no production). Examples are alpha thalassemia and beta thalassemia. 47