Synthesis of pyrimidines and purines
- 1. Synthesis of Pyrimidines and Purines
- 2. Nucleotides: ---- Nitrogenous Base ---- Pentose Monosachharides ---- One/Two or Three Phosphate Groups Nitrogeneous Bases PURINES PYRIMIDINES
- 3. Purine and Pyrimidine Structure Both DNA and RNA contain the same Purine bases : Adenine (A) and Guanine (G) Both DNA and RNA contain the same Pyrimidine structure cytosine (C), differ in their second Thymidine base : DNA contains Thymine (T) RNA contains Uracil (U) Nucleosides: Addition of Pentose sugar to a base through a Glycosidic bond produces a Nucleoside. E.g: Ribonucleoside,Deoxyribonucleoside.
- 4. Functions Participate in metabolic functions as diverse as energy metabolism, protein synthesis, regulation of enzyme activity, and signal transduction. Linked to vitamins or vitamin derivatives, nucleotides form a portion of many coenzymes. ATP and ADP are the principal players in the energy transductions that accompany metabolic interconversions and oxidative phosphorylation. Cyclic nucleotides cAMP and cGMP serve as the second messengers in hormonally regulated events. Medical applications : Use of synthetic purine and pyrimidine analogs that contain halogens, thiols, or additional nitrogen atoms in the chemotherapy of cancer and AIDS, and as suppressors of the immune response during organ transplantation.
- 6. Can Cells Synthesize Purine Nucleotides?? Nearly all organisms synthesize purines and pyrimidines “denovo biosynthesis Pathway“. Many Organisms also “Salvage”purines from diet and degradative pathways.
- 7. Your Text here How do Cells synthesize the Purine Nucleotides??
- 8. Synthesis of Purine Nucleotides denovo Synthesis Total Ten Steps in synthesis of Purine Nucleotide. Salvage Pathway
- 9. A. Synthesis of 5-Phosphoribosyl -1- pyrophosphate
- 10. B. Synthesis of 5-Phosphoribosylamine Committed step in Purine Synthesis.
- 11. C. Synthesis of Inosine Monophosphate, the “PARENT’ Purine Nucleotide Next Nine steps in Purine biosynthesis leads to formation of Inosine Monophosphate(IMP). Four Steps require ATP as an energy source and two steps in the pathway require N10-formyltetrahydrofolate as a one carbon donor.
- 12. Synthesis of Adenosine and Guanosine Monophosphate Two step Energy-requiring pathway. Synthesis of AMP requires GTP and Synthesis of GMP requires ATP Cross Regulation
- 13. If both AMP and GMP are present in adequate amounts, the denovo pathway of purine synthesis is TURNED OFF at the Amidotransferase step.
- 17. Synthetic Inhibitors of Purine Synthesis Sulfonamides Methotrexate Designed to inhibit the growth of rapidly dividing microorganisms without interfering with human cell functions.
- 18. How is Pyrimidine synthesized???? In contrast to Purine ring, Pyrimidine ring is completed before the addition of 5-ribose Phosphate. Carbamoyl Phosphate and Aspartate are the precursors of the Six-membered Pyrimidine Ring.
- 19. A. Synthesis of Carbomyl Phosphate Glutamine + CO2 C Carbomyl Phosphate Synthetase II Regulated Step in this pathway. Carbomyl Phosphate
- 20. • Your Text here • Lorem ipsumconsectetuer CPS I CPS II Cellular Location Mitochondria Cytosol Pathway Involved Urea Cycle Pyrimidine Synthesis Source of Nitrogen Ammonia Glutamine Regulators Acivator: N-acetyl- Glutamate Activator :PRPP Inhibitor : UTP Comparison between CPS I and CPS II
- 21. B. Synthesis of Orotic Acid Second Step Formation of CarbomylAspartate.
- 22. C. Formation of a Pyrimidine Nucleotide Orotidine Monophosphate(OMP) Parent Pyrimidine mononucleotide formed from Completed Pyrimidine ring. OMP Orotidylate Decarboxylase Uridine Monophosphate (UMP) removes carboxylic group. Orotate Phosphoribosyltransferase and Orotidylate Decarboxylase are also catalytic domains of a single Polypeptide chain called UMP Synthase.
- 23. Orotic Aciduria Deficiency of one or both activities of the Bifunctional Enzyme Orotic Acid in Urine. UMP thus formed is converted to UDP and UTP.
- 24. D. Synthesis of Cytidine Triphosphate UTP Amination Cytidine Triphosphate (CTP)
- 25. • Your Text here • Lorem ipsumconsectetuer E. Synthesis of Deoxythymidine Monophosphate dUMP Thymidylate synthase dTMP
- 27. • Your Text here • Lorem ipsumconsectetuer Q. The rate of DNA synthesis in a culture of cells could be most accurately determined by measuring the incorporation of which of the following radiolabeled compounds? A. Adenine. B. Guanine. C. Phosphate. D. Thymidine.
- 28. • Your Text here • Lorem ipsumconsectetuer Q. A 1-year-old female patient is lethargic, weak, and anemic. Her height and weight are both low for her age. Her urine contains an elevated level of orotic acid. The administration of which of the following compounds is most likely to relieveher symptoms? A. Adenine. B. Guanine. C. Hypoxanthine. D. Thymidine. E. Uridine.
- 29. • Your Text here • Lorem ipsumconsectetuer