Purine and Pyrimidine biosynthesis

Nucleotide Biosynthesis involves 2 processes. one is Denovo synthesis and other is Salvage pathway. An outline of both the processes has given in this presentation.

1. Welcome It’s Great to have you here!!!

2. Purine and Pyrimidine Biosynthesis Course no. - MBB-591 Course Title - Master Seminar (0+1) Presented By- Sripati Abhiram Sahoo I.D No- 120116215 Course Instructor- Prof. Anil S. Kotasthane 2

3. Outline Introduction What are Purine and Pyrimidine bases Molecular structure of Purine and pyrimidine bases Nucleosides and Nucleotides Synthesis of Purine nucleotides Synthesis of Pyrimidine nucleotides Flowchart of biosynthesis of nucleotides 3

4. Introduction Pyrimidine and purine are the names of the parent compounds of two types of nitrogen-containing heterocyclic aromatic compounds. N N Pyrimidine N N N N H Purine 4

5. Important Purines Adenine and guanine are the principal purines of both DNA and RNA . Caffeine (coffee) and theobromine (cocoa) are naturally occurring purines. N N N H 2 N N H Adenine O H N N H N N H 2 N Guanine 5

6. Important Pyrimidines Pyrimidines that occur in DNA are cytosine and thymine. Cytosine and uracil are the pyrimidines in RNA . H N N H O O Uracil H N N H O O CH 3 Thymine H N N H N H 2 O Cytosine 6

7. Nucleosides and Nucleotides Nucleoside is a structure formed by the combination of nitrogen base and sugar where as Nucleotides are phosphoric acid esters of nucleosides . N2 base Sugars Nucleoside Adenine Deoxyribose /Ribose Adenosine Guanine Deoxiribose /Ribose Guanosine Thymine Deoxyribose Thymidine Cytosine Deoxyribose /Ribose Cytidine Uracil Ribose Uridine Nucleoside Phosphoric acid Nucleotides Adenosine Phosphoric acid Adenylate (AMP) Guanosine Phosphoric acid Guanylate ( GMP) Thymidine Phosphoric acid Thymidylate ( TMP) Cytidine Phosphoric acid Cytidylate (CMP) Uridine Phosphoric acid Uridylate (UMP) 7

8. Synthesis of Purine N ucleotides 8

9. Sources of Different A toms of Purine Ring 9

10. De novo Synthesis o f Purine And Pyrimidine 10

11. Purine Synthesis STEP-1 STEP-2 11

12. STEP-3 STEP-4 STEP-5 STEP-5 12

13. STEP-6 STEP-7 13

14. STEP-8 STEP-9 14

15. STEP-10 STEP-11 15

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17. Salvage Pathway It refers to the formation of purine nucleotides by the Addition of ribose phosphate ( from PRPP) to the preformed purine bases. Addition of phosphate to the preformed purine nucleosides. Significance Salvage pathway provide a pathway for the utilization of purine bases derived from diet (exogenous) and normal turnover of the nucleic acids. In erythrocytes, denovo syntheis of purine nucleotides does not occur because of absence of PRPP amidotransferase . The requirement of purine nucleotides is met by the salvage pathway. 17

18. Synthesis of P yrimidine N ucleotides 18

19. Sources of different atoms of pyrimidine ring 19

20. Pyrimidine Synthesis 20

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23. Salvage pathway 23

24. Summary 24

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