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HEMOGLOBIN

HEMOGLOBIN. Heme molecule. Fe. HAEMOGLOBIN. INTRODUCTION STRUCTURE TYPES SYNTHESIS FATE DERIVATIVES CLINICAL- ANAEMIAS - HAEMOGLOBINOPATHIES - PORPHYRIAS. Pigment present inside RBCs Carries O 2 and CO 2

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HEMOGLOBIN

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  1. HEMOGLOBIN Heme molecule Fe

  2. HAEMOGLOBIN • INTRODUCTION • STRUCTURE • TYPES • SYNTHESIS • FATE • DERIVATIVES • CLINICAL- ANAEMIAS - HAEMOGLOBINOPATHIES - PORPHYRIAS

  3. Pigment present inside RBCs • Carries O2 and CO2 • Responsible for red color of blood • Deficiency is called anaemia

  4. Structure: Mol Wt: 68,000 4 heme : 1 mol of Hb contains 4 iron atoms and carry 4 molecules (8 atoms) of O2 Iron : Ferrous state Combination of heme with O2(Oxygenation not oxidation) Globin: Hb A ( 2 2) each  - 141 Amino acids each  - 146 Amino acids Globin hemoglobin Ferrous iron Haem Protoporphyrin (4 pyrrole rings)

  5. Formation of hemoglobin 2 succinyl-CoA + 2 glycine pyrrole 4 pyrroleprotoporphyrinIX Protoporphyrin IX + Fe heme 4 heme + polypeptide hemoglobin chain 2 alpha chains + 2 beta chains hemoglobin A

  6. Factors controlling synthesis of hemoglobin 2. Minerals: a) Iron : 1gm % of Hb – 1.34 mg b) Copper : Absorption, mobilization & utilisation of Iron. c) Cobalt : Manufacture of Vit B12 ,  erythropoietin d) Calcium :  iron absorption 3.Vitamins: Vit C converts ferric iron of food into ferrous state 1. Proteins,

  7. Haem

  8. DERIVATIVES OF HEMOGLOBIN • Oxy Hb : HbO2, influenced by pH, temperature,concentration of 2,3 DPG (2,3 Diphosphoglycerate) • CarbaminoHb : CO2 + Hb NH2HbNHCOOH • Reduced Hb : Deoxygenated Hb.

  9. DERIVATIVES OF HEMOGLOBIN ( Contd) • CarboxyHb : Hb reacts with CO ( 250 times more affinity) • Methemoglobin: Reduced or Oxygenated Hbis exposed to Oxidising agents. Fe 2+ Fe3+HbOH • Hb A1C: This is useful in detecting the glycemic control in Diabetes mellitus patients.

  10. Types of Hemoglobin Normal Types: • Adult Hb: a) Hb A (2 2) b) Hb A2 (2 2) • Fetal Hb: Hb F(2 2 ) a) > affinity for O2 b) life span < 1- 2 weeks c) at birth – 80 % Abnormal Types: • Hemoglobinopathies : abnormal polypeptide chains. • Thalassemias : pp chains small amounts or absent • Hb S : Sickle cell anemia - chain, glutamic acid replaced by valine in the 6th position.

  11. TYPES OF HEMOGLOBIN • HbA- Adult Type- α2β2 • HbA2- 2% of adult Hb- α2δ2 • HbF- Foetal Type- α2γ2 • Hb gower1- ε2ζ2 • Hb gower2- ζ2β2

  12. FATE OF HAEMOGLOBIN • RBCs are destroyed in RES ( mainly spleen and bone marrow) after 120 days of life. • Macrophages phagocytose – hemolyse - degrade haemoglobin – form Bilirubin – transport to liver with albumin – conjugated and detoxified – secreted in bile.

  13. FUNCTIONS OF HEMOGLOBIN • 1. Transports O2 from lungs to tissues in the form of oxy-hemoglobin • 2. Transports CO2 from tissues to lungs in the form of carbamino-Hb- 30% of total CO2 transport • 3. Acts as a buffer- important in acid-base balance- 6 times more than plasma proteins

  14. NORMAL VALUES • At Birth : 23gm % • End of 3 months : 10.5 gm % • End of 1 year : 12.5 gm % • Adults : Males – 14 -18 gm % Females – 12 -15 gm % Clinically 14.8 gm % is 100% • O2 carrying capacity of blood: 1gm % of Hb = 1.34 ml of O2

  15. APPLIED ASPECTS • Normal Hb value : Males 14 – 18 gm/dL Females 12 – 16 gm/dL # ANAEMIAS # HAEMOGLOBINOPATHIES # PORPHYRIAS

  16. ANAEMIAS Classification: I . Based on severity. • Mild – 8-12gm/dL • Moderate – 5-8gm/dL • Severe - < 5gm/dL

  17. II) Based on morphology of RBCs • Normocytic normochromic – eg. Acute blood loss • Macrocytic – eg Vit B12 & Folic acid deficiency • Microcytic hypochromic – iron deficiency anaemia

  18. III) Based on aetiology : • Blood loss – RTA, Surgeries • Haemolytic anaemias – congenital, malaria • Bone marrow depression- Aplastic anaemia • Nutritional anaemias- iron deficiency, megaloblastic, • Genetic causes- thalassaemia

  19. HAEMOGLOBINOPATHIES Sickle cell anaemia: Valine replaces glutamate in the 6th position of β chain. • Is common in African blacks • Confers resistance against malaria • Hb crystallizes & takes sickle shape under hypoxic conditions. • Increased RBC sequestration

  20. THALASSAEMIA • Reduced or absent synthesis of globin chains. Types:-alpha & Beta - Major & Minor β-thalassemia major cooley’s anaemia Treatment  # Transfusion – packed red cell is preferred. # Splenectomy # Bone Marrow Transplant

  21. PORPHYRIAS • DEF: Inherited disorders involving specific enzymes in heme biosynthetic pathway • TYPES: • a) Hepatic porphyrias i) ALA dehydratase deficient porphyrias ii) Acute intermittent porphyrias iii) Porphyria cutanea tarda b) Erythropoetic porphyrias i) X-linked sideroblastic anemias ii) Congenital erythropoetic porphyrias

  22. Other molecules containing Haem:- i) Myoglobin – present in muscles - combination with single polypeptide chain. ii) Neuroglobin – present in CNS iii) Cytochrome enzymes – present in mitochondria iv) Peroxidases

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