Nucleotide Synthesis (De-novo and Salvage Pathways of Purine & Pyrimidine Biosynthesis PPT by easybiologyclass) 1. NUCLEOTIDE BIOSYNTHESIS Bio-synthesis of Purines & Pyrimidines e-mail: easybiologyclass@gmail.com mail@easybiologyclass.com www.easybiologyclass.com www.easybiologyclass.com The purine ring is synthesized along with the nucleotide i.e. Split-thickness rabbit skins were minced and incubated in vitro with radioactive precursors selected to measure de nova and salvage pathways for pyrimidine nucleotide synthesis. De novo synthesis of nucleotides does not take place in brain and erythrocytes, making salvage pathway indispensable for them The salvage pathway requires no ATP and accounts for 90% of nucleotide biosynthesis. De Novo Synthesis: De novo (all over again) synthesis of purine nucleotides is synthesis of purines anew. Each category has at least one description. Salvage pathway (recycle pathway): used to recover bases and nucleosides formed during the degradation of RNA and DNA APRT is inhibited by AMP. A salvage pathway is a pathway in which a biological product is produced from intermediates in the degradative pathway of its own or a similar substance. This pathway supplies ribose sugar for the formation of the nucleotide. Uridine monophosphate, or UMP, is used as the example of the pyrimidine nucleotide. II. Both purines and pyrimidines can be synthesized by 2 alterative pathways: the de novo pathways that metab-olize ribose and amino acids in a series of enzymatic reactions and the salvage pathways that The salvage of pyrimidine bases has less clinical significance than that of the purines, owing to the solubility of the by-products of pyrimidine catabolism. recycling of the bases. UMP, which is used to synthesize UDP, UTP, dTTP, CTP, and dCTP, is the common metabolite between the de novo and the salvage pyrimidine synthesis pathway. (1) de-novo synthesis and (2) synthesis by salvage pathways. Understand the Two Pathways of nucleotide biosynthesis (1) De-novo synthesis and (2) Salvage Pathways. The abbreviation PRPP is used for 5-phosphoribosyl-1-pyrophosphate. attached to the ribose sugar provided from HMP pathway. (2) Salvage process i.e. I. De-novo synthesis (synthesis from scratch): it is a biochemical pathway in which nucleotides are synthesized new from simple precursor molecules. HGPRT is the most important salvage enzyme. However, as indicated above, the salvage pathway to thymidine nucleotide synthesis is especially important in the preparation for cell division. Classify each description as the de novo pathway, salvage pathway, or both pathways of pyrimidine nucleotide synthesis. 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