Heme degradation pathway- I.pptx_Nursing students

Infant jaundice is yellow discoloration of a newborn baby's skin and eyes. Infant jaundice occurs because the baby's blood contains an excess of bilirubin (bil-ih-ROO-bin), a yellow pigment of red blood cells.

1. H eme catabolism and H eme Degradation Pathway By, Mr. Abhijit Bhoyar Associate Professor 1

2. Specific Learning objectives At the end of the lecture students will be able to Describe the heme structure Explain the structure & function of hemoglobin Discuss the role of nucleic acids Illustrate biosynthesis of proteins

3. Introduction Hemoglobin – red coloring matter of blood Present in RBC Conjugated protein – heme & globin Molecular weight = 64,450 Can combine with O Transport of O within blood

4. Combination of two structures Structure of Heme Structure of globin – protein Structure of Hemoglobin

5. Structure of Heme An iron porphyrin – cyclic compound Porphyrin = tetra pyrrole ring like structure 4 pyrrole rings are linked through methylene or methylidene bridges Outer C atoms are not linked and numbered as 1-8

6. Structure of Heme Iron in the ferrous state is bound to nitrogen atom of the pyrrole rings Structure of Globin Globin is protein part of hemoglobin Composed of 4 parallel layers of closely packed polypeptide chians 2 chains have identical AA composition of 141 AA Remaining 2 have 146 AA each Total no. of AA in globin is 574

7. Structure of Globin Alpha chains 2 chain Beta chains 2 chain Hb molecule & sub-units contain hydrophobic AA internally & hydrophyllic AA on their surfaces The resulting heme pockets provide for entry of O2

8. Properties of Hemoglobin Oxyhemoglobin – Hb + O 2 - Transport of O to different parts of the body Formaton of Carbamino compound – Hb+C O 2 Reaction with CO – Forms Carboxy -hemoglobin – prevents formation of oxyhemoglobin – dangerous to inhale even small amounts of CO Buffering Action – Hb + O 2

9. Buffering Action – 1 mole of Hb contains 35 histidine residues – exerts buffering action – Hb play imp in regulating acid-base balance of blood Formation of methemoglobin – by oxidaton of Hb – cannot carry O – methemoglobin is reduced to Hb by Vit . C

10. Biosynthesis of hemoglobin In bone marrow – erythroid cell during development of erythrocyte Iron in Ferrous state incorporated into protoporphyrin to form Heme Heme attached to newly formed Globin = Hb

11. Biosynthesis of Proteins 3 phases 1)Initiation Dissociation of ribosomes Formation of 40s preinitiation complex Formation of 40s initiation complex Formation of 80s initiation complex

12. 2)Elongation Binding of Aminoacyl - tRNA to A siter Peptide bond formation Translocation 3)Termination

13. Role of Nucleic Acids in Biosynthesis of proteins 2 types of NA DNA Deoxyribonucleic acid RNA Ribonucleic acid

14. Functions of Nucleic acids DNA - chemical basis for heredity Reserve bank of genetic information Responsible for maintaining the identity of different species Control every cellular function Organized into genes – the fundamental units of genetic information Control protein synthesis through mediation of RNA

15. Components of Nucleic acids NA – polymers of nucleotides Nucleotides – composed of a nitrogenous base, a pentose sugar & a phosphate A nitrogenous base + a pentose sugar = nucleoside Nucleotide = nucleoside + phosphate Nitrogenous bases – aromatic, heterocyclic compounds

16. Functions of Nucleotides Building blocks of nucleic acids Structural components of several coenzymes Serve as carriers of high energy intermediates in the biosynthesis of CHO, lipids & proteins

17. Functions of Nucleotides Involved in the energy reactions of the cell – ATP is energy currency As allosteric regulators – control several metabolic reactions Cyclic AMP & Cyclic GMP = second messengers in hormonal functions

18. Structure of Nucleotides Nitrogenous bases – two types Purines Adenine (A) Guanine (G) Pyrimidines Cytosine (C) found in both DNA & RNA Thymine (T) in DNA Uracil (U) in RNA

19. Difference between DNA & RNA DNA Sugar – deoxyribose Pyrimidine – thymine Double stranded structure Number of Guanine equals Number of cytosine = Chargaff’s rule - obeyed Reservoir of genetic information Genes control protein biosynthesis RNA Ribose sugar Pyrimidine – uracil Usually single stranded structure Guanine content is not equal to cytosine = Chargaff’s rule – not obeyed Identified by Orcinol color reaction 3 different types – based on cellular composition Responsible for transfer of genetic material Synthesized from DNA Involved in protein biosynthesis

20. Types of RNA Messenger RNA = mRNA Synthesized in nucleus Enter the cytoplasm to participate in protein synthesis High molecular weight with short half-life Transfer RNA = tRNA Molecular wt = 25000 20 species of tRNA corresponding to 20AA Contains 4 arms Structure resembles clover leaf

21. Ribosomal RNA = rRNA Ribosomes = factories of protein synthesis Play significant role in binding of mRNA to ribosomes Responsible for protein synthesis

22. Expected Question Essay /Situation Question Explain the structure & function of hemoglobin Explain Nucleic Acids in Biosynthesis of proteins Short Question Explain heme and chlorophylls. Describe biosynthesis of proteins in the cells and role of nucleic acids in protein synthesis . Defference between DNA&RNA

23. THANK YOU