“The formation of DNA’s structure by Watson and Crick may turn out to be the greatest developments in the field of molecular genetics in recent years”
Linus Pauling, 1953
Purines (Adenine & Guanine) and pyrimidines (Thymine, Cytosine & Uracil) are the two classes of nucleotides which forms the nucleic acids (DNA & RNA) in the cells. Apart from the primary role of DNA and RNA as “genetic information storage”, nucleotides also serves different functions in the cells such as energy carrier (ATP and GTP), components of co-enzymes (NAD and FAD) and cellular signal transduction (cAMP and cGMP as ‘second messengers’). An ample supply of nucleotides in the cell is very essential for all the cellular processes. This post discuss the biosynthesis of Purines and Pyrimidines in an EASY but detailed way.
Pathways for the biosynthesis of nucleotides
Nucleotide biosynthesis in the cell can be grouped into two broad classes. (1) de-novo synthesis and (2) synthesis by salvage pathways.
I. De-novo synthesis (synthesis from scratch): it is a biochemical pathway in which nucleotides are synthesized new from simple precursor molecules.
II. Salvage pathway (recycle pathway): used to recover bases and nucleosides formed during the degradation of RNA and DNA