Hemoglobin Introduction
Structure of Hemoglobin
Functions of Hemoglobin
Heme containing Compounds
Hemoglobin & Derivatives
DR. S. Irfan Raza
Hemoglobin (Hb)
Hemoglobin is found exclusively in RBCs
Its main function is to transports O2 and CO2 between lungs
and various tissues.
Normal concentration of Hb-A (Major Hemoglobin) in Adults
Adult males: 135 – 175 g/L 13.8 to 17.2 (g/dL)
Adult females: 120 – 168 g/L 12.1 to 15.1 (g/dL)
Hemoglobin Structure & Functions
It is an oxygen/CO2 carrier protein present in the RBCs of blood. It is a
conjugated chromo-protein having heme as its prosthetic group.
Heme is the prosthetic group, not only of hemoglobin but also of myoglobin,
cytochromes etc.
Hemoglobin Functions
Its performing two important functions:
1. Delivery of Oxygen
2. Transport of CO2
Hemoglobin Structure
Properties of iron in heme
Fe forming how many coordination complexes?
Coordination number of
iron in heme = 6
6 bonds:
• 4x pyrrole ring (A,B,C,D)
• 1x link to a protein
• 1x link to an oxygen
Quaternary Structure of Hemoglobin
•Hb comprises of:
•1. dimer of (αβ)1 2. dimer of (αβ)2
•Each dimer is held together by:
•Many Hydrophobic interactions.
Compounds Containing Heme Group
Hb
Peroxidases
Mb
Heme
containing
Compounds
Catalases Cyto
Hemoglobin Derivatives
Hb
CO Met
Hb HB
Methemoglobin
When hemoglobing has Fe3+ state i.e., Methhemoglobin loses its
ability to release oxygen. Patient suffers with methemoglobinmia
in which Hemoglobin cant release oxygen to tissues effectively.
Methemoglobin Causes
H2O2
Free
Bromates Methhemoglobin Radicals
Chlorayes
CO is a toxic compound and has 200 times higher affinity than O2 for Binding with Hb.
Carboxyemoglobinemia
Headache
Irritability Nausea
CO
Hemoglobin
Breathless
Vomiting ness
Abnormal Hemogobins
Sickle Cell
anemia
Hemoglobino
pathies
Thelasse
Porphyria's
mias
Viva Questions:
Define hemoglobin and its structure
What Methemoglobin and related clinical conditions
What is Carboxyhemoglobin and its causes and related
clinical conditions
Enlist Hemoglobinopathies.
How body converts methemoglobin back to
hemoglobin.
Thank You.
Lecture - 2 Hemoglobin Related Diseases
Dr. Syed Irfan Raza
Abnormal Hemoglobin
Sickle Cell Anemia
Occurrence
Molecular Basis – Homozygous & Heterozygous states
Sickle Cell Related Abnormalities
Mechanism of Sickling
Sticky Patches
Types of Normal Hb
Types of Abnormal Hb
Sickle Cell trait provides resistance to malaria
HbS diagnosis
Management
Hemoglobin c disease
Hemoglobin D
Hemoglobin E
Normal Major Types of Hb
HbA1
90%
HbA1c
Normal HbA2
Hb 5%
HbF2%
Sickle Cell Trait Provides Resistance To Malaria
HbS Shorter life span
HbS has low pH cause sickling of HbS cell which results into
lysis
Low Intra HbS K+ level
Sickling Test:
Microscopic examination of blood (Na-dithionite)
Diagnosis
Electrophoresis - @ pH8.6 HbS moves slowly towards anode
– HbS less negative.
Management
1. Use of Sodium Cyanate
Na-cyanate inhibit sickling of erythrocytes.
Cyanate increases the affinity of O2 to HbS &
lowers the formation of deoxy HbS – side effect of peripheral
nervous system
Patients with severe anemia needs repeated blood transfusion
which result into iron over load leads to cirrhosis of liver.
Abnormal Hemoglobin Types
HbS
HbE Hb HbC
HbD
Hemoglobin C Disease
Hemoglobin C disease is a condition affecting a protein in the blood
(hemoglobin) which transports oxygen throughout the body.
Symptoms of this condition can include fatigue, weakness,
and anemia .
The spleen can also become enlarged as a result of this disease.
Cooleys hemoglobinemia (HbC)
Genetic Alteration
Glu – Lys @ 6th position of B chain.
Occurrence: Only in blacks
Characterized by mild hemolytic anemia.
Therapy Availble: No therapy
Hemoglobin E:
Hemoglobin E (HbE) is an abnormal hemoglobin with a single
point mutation in the β chain.
Most common abnormal hemoglobin after HbS.
Occurrence:
10% of south east Asia population.
Indian, Sri Lankan and Bangladeshi, few areas of Pakistan
Genetic Mutation:
Glu – Lys @ 6th AA – B-chain.
Clinical Importance:
No clinical manifestation.
Hemoglobin D:
Genetic Mutation:
121 codon (GAA→CAA)
Glu – Gln @ 121st AA – B-chain.
There can be several variants from different places
(HbD – Punjab), (HbD – LosAngles)
Diagnosis-
On electrophoresis moves along with HbS.
Types of Normal Hemoglobin
Enlist abnormal hemoglobin
Which type of Abnormal hemoglobin is
most common
Which type of hemoglobin is common in
Pakistan
How Abnormal hemoglobin can be
identified
How HbS provides resistance to malaria
What is thalassemias?
