Hemoglobin is the protein in red blood cells that carries oxygen from the lungs to tissues and carbon dioxide back to the lungs. Fetal hemoglobin differs from adult hemoglobin in its structure and oxygen affinity. Fetal hemoglobin is composed of two alpha and two gamma chains, has a shorter lifespan, and greater oxygen affinity to facilitate more oxygen delivery to the developing fetus. After birth, fetal hemoglobin production switches off and is replaced by over 90% adult hemoglobin composed of two alpha and two beta chains with lower oxygen affinity.

1. STRUCTURE OF HEMOGLOBIN &
NORMAL RANGE DIFFERENCE
BETWEEN FETAL AND ADULT
HEMOGLOBIN
Abdul Qadir Khan
Roll No. 04
Batch 2016-17

2. Learning Objective
 Introduction.
 Structures Of Hemoglobin.
 Types Of Hemoglobin.
 Differences between Fetal and Adult
Hemoglobin.
 Bibliography.

3. Introduction
Hemoglobin is the protein
molecule in red blood cells that
carries oxygen from
the lungs to the body's tissues
and returns carbon dioxide
from the tissues back to the
lungs.

4. Basic chemical steps in the formation of
hemoglobin.
• First, succinyl-CoA, formed in the krebs metabolic cycle, binds with
glycine to form a pyrrole molecule.
• In turn, four pyrroles combines to form protoporphyrin IX, which
then combines with iron to form the heme molecule.
• Finally, each heme molecule combines with a long polypeptide
chain, a globin synthesized by ribosomes, forming a subunit of
hemoglobin called hemoglobin chain.

5. • The primary function of hemoglobin in the
body is to combine with oxygen in the lungs
and then to release this oxygen readily in the
peripheral tissue capillaries, where the
gaseous tension of oxygen is much lower than
in lungs.
• Oxygen does not combine with the two
positive bonds of the iron in the hemoglobin
molecule.

6. • It binds loosely with one of the so-called
coordination bonds of the iron atom.
• This is an extremely loose bond, so the
combination is easily reversible.
• The oxygen does not become ionic oxygen but is
carried as molecular oxygen to the tissues.
• Because of the loose, readily reversible
combination, it is released into the tissue fluids
still in the form of molecular oxygen rather than
ionic oxygen.

7. Structure Of Hemoglobin
• The moleculer weight of hemoglobin is
64,458.
• It is made up of two components:
i) Heme and ii) globin.
• Heme is a tetra-pyrrole structure with a
central iron atom attached to four
nitrogen atoms from four pyrrole rings.

8. • Globin is a protein containing two pairs of
polypeptide chains. It binds to the same iron
atom that binds the pyrrole rings.
• One heme and one globin chain form a subunit.
• Four such subunits form a hemoglobin
structure.

10. • There are several slight variations in the different
subunit hemoglobin chains, depending on the
amino acid composition of the polypeptide portion.
• The different types of chains are designated Alpha
chains, Beta chains, Gamma chains, and Delta
chains.
• The most common form of hemoglobin in the adult
human being, hemoglobin A.
• The most important feature of the hemoglobin
molecule is its ability to combine loosely and
reversibly with oxygen.

11. Types Of Hemoglobin
1. Adult Hemoglobin (HbA)
2. Fetal Hemoglobin (HbF- α2γ2)
3. Hemoglobin-S (HbS)
4. Miscellaneous Hemoglobin

12. Difference between Fetal
& Adult Hemoglobin
• Hemoglobin A is composed of two alpha
and two beta chains while Hemoglobin F is
composed of two alpha and two gamma
chains.
• Fetal hemoglobin life span is less (about 80
days) as compared to that of HbA (120
days).
• Fetal Hb has greater affinity for oxygen as
compare to the Adult Hb mainly to
facilitate more oxygen supply to the
developing fetus.

13. • The fetal hemoglobin production is switched
off after birth, after that a normal child
start producing Adult hemoglobin.
• Adult hemoglobin is present in major amount
almost above 90% in normal human after
birth, while fetal hemoglobin is decreased to
2% due to production of adult hemoglobin.

14. Bibliography
• Guyton & Hall
• A K Jain
• D. Venkatesh
• Google Images