This document provides an overview of nucleic acid chemistry concepts including: 1) Purines and pyrimidines are the basic structures that make up nucleotides and nucleic acids. Major purines include adenine and guanine, while major pyrimidines include cytosine, uracil, and thymine. 2) Nucleosides consist of a nitrogenous base linked to a ribose or deoxyribose sugar. Nucleotides contain a nitrogenous base, sugar, and phosphate group. 3) Important nucleotides include ATP, ADP, cAMP, GTP, and CTP which play critical roles in cellular energy transfer and signaling. Synthetic analogs are also used experimentally and clinically.

1. Dr. Vishnu Kumar
Professor & Head, Department of
Biochemistry, MPTMC, SIDDHARTH NAGAR
vkawasthi@hotmail.com
madhwapur1976@gmail.com
Nucleic Acid Chemistry
Competency Number BI: 7.1
CORE COMPETENCY

2. LEARNING OBJECTIVES
After completion of this lecture learner
should be able to define/describe:
 Purines and Pyrimidines
 Major & minor Purines
 Major & Minor Pyrimidines
 Nucleosides & Nucleotides
 Synthetic Analogs of nucleotides

3. Purines & Pyrimidines
 Cyclic compounds containing
Nitrogen, Carbon and other elements.
Their principal derivatives are
nucleosides and nucleotides.

4. Purine ring

6. Major Purines
 Adenine– 6-amino purine.
 Guanine—2 amino,6 oxo purine.
 Xanthine– 2,6 dioxo purine.
 Hypoxanthine– 6 oxo purine.

8. Major Pyrimidines
 Cytosine– 2 oxo, 4 amino pyrimidine.
 Uracil ----2,4 dioxo pyrimidine.
 Thymine – 2,4 dioxo 5 methyl
pyrimidine.

10. Minor bases
 Purines– Hypoxanthine, Xanthine & uric
acid
 Pyrimidines– 5 methyl cytosine, Pseudo
uracil.

11. Nucleosides & Nucleotides
 Nucleosides – compounds containing
nitrogenous base and ribose or deoxy
ribose.
 Nucleotides – N base + ribose or deoxy
ribose + phosphate.

12. Nucleosides
 Purine or Pyrimidine bases & ribose or
deoxy ribose sugar linked by glycosidic
linkage.
 Linkage is between N 9 of purine or N I
of pyramiding with carbon 1 of sugar.

13. Purine Nucleosides
 Adenosine--- adenine + ribose or Deoxy
ribose.
 Guanosine--- guanine +ribose or deoxy
ribose.
 Inosine --- Hypoxanthine +ribose or
deoxy ribose.
 Xanthosine --- xanthine +ribose/ deoxy
ribose.

15. Purine Nucleotides
Adenosine mono phosphate (Amp)–
Adenine + sugar + phosphate.
Guanosine mono phosphate (GMP)–
Guanine + sugar + phosphate.
Hypixanthine mono phosphate (IMP)---
Hypoxanthine + sugar + phosphate.

17. Pyrimidine Nucleosides
cytidine– Cytosine + Ribose/ Deoxyribose.
Uridine – Uracil + Ribose.
Thymidine– Thymine + Deoxyribbose.

19. Pyrimidine nucleotides
 Cytidine mono phosphate (CMP)–
cytosine + sugar + phosphate.
 Uridine mono phosphate (UMP)– Uracil
+sugar +phosphate.
 Thymidine mono phosphate (TMP) –
Thymidine + sugar+ phosphate.

20. Physiologically Important
Nucleotides/Nucleosides
 ADENOSINE DERIVATIVES.
 ATP– Principal biological transducer of
energy.
 ADP – Precursor of ATP.
 CAMP--- Acts as 2nd messenger in hormone
action.
 S adenosyl metheonine —Methyl donor.

21. Other important nucleotides.
 GTP-- Energy Source.
 CGMP--Acts as 2nd messenger in hormone
action.
 UDP– UDP Glucose, UDP Glucuronic acid.
 CTP– synthesis of phospholipids.
 Vitamin nucleotides– NAD, NADP,
FAD,Coenzyme –A.

24. Synthetic Analogs of
nucleotides
 5-Fluro uracil.
 5 Iodo uracil.
 6-thio guanine.
 6- mercapto purine.
 Allopurinol.
 AZT– Azido di deoxy thymidine.
 Di deoxy thymidine.
yS

25. Nucleic Acids
 Polymers of Nucleotides, linked by phospo
diester linkages, which link successive
nucleotides in which 5’ phosphate group of
one nucleotide unit is joined to 3’ hydroxyl
group of the next nucleotide.
 Prime ( ‘) means position on the ribose
molecule.
 For example—3’ AMP means phosphate is
attached to the 3rd position of ribose.

27. Deoxy ribonucleic acid.
(DNA)
 Discovered in 1953 by Watson &Crick.
 Function – stores and transmits genetic
information.
 Evidenced by Avery ,Macleod & McCarty
in 1944.

28. Definition
 Polymer of deoxy ribonucleotides
(A,G,C,T.) linked by phospho diester
linkage. Double stranded, two strands
are linked by hydrogen bonds.
 Carries and transmits genetic
information.