BIOSYNTHESIS OF PURINES AND PYRIMIDINES

BIOSYNTHESIS OF PURINES AND PYRIMIDINES

• The DNA and RNA consist of repeating units called Nucleotides, each of which consists of a Purine or Pyrimidine, Pentose (five -carbon sugar), and Phosphate group.
• Purines (Two ring) and Pyrimidines (One ring) are the nitrogen-containing "bases" found in the nucleotides that make up DNA and RNA.
• The five-carbon sugars of Nucleotides are derived from either the Pentose phosphate pathway or the Entner - Doudoroff pathway.
• Certain Amino acids like Aspartic acid, Glycine, and Glutamine - made from intermediates produced during Glycolysis and in the Kreb’s cycle participate in the biosynthesis of Purines (Adenine & Guanine) and Pyrimidines (Cytosine, Thymine & Uracil).
• The carbon and nitrogen atoms derived from these amino acids form the Purine and Pyrimidine rings, and the energy for synthesis is provided by ATP.
• DNA contains all the information necessary to determine the specific structures and functions of cells.
• Both RNA and DNA are required for protein synthesis. In addition, such nucleotides as ATP, NAD+, and NADP+ assume roles in stimulating and inhibiting the rate of cellular metabolism.

Biosynthesis of Purines and Pyrimidines