nucleotide_metab_1

Nucleotide_metab_1 - Nucleotide Metabolism QuickTimeª and a GIF decompressor are needed to see this picture Roles of Nucleotides • Precursors to

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Unformatted text preview: Nucleotide Metabolism QuickTimeª and a GIF decompressor are needed to see this picture. Roles of Nucleotides • Precursors to nucleic acids (genetic material and non-protein enzymes). • Currency in energy metabolism (eg. ATP, GTP). • Carriers of activated metabolites for biosynthesis (eg. CDP, UDP). • Structural moieties of coenzymes (eg. NAD, CoA). • Metabolic regulators and signal molecules (eg. cAMP, cGMP, ppGpp). Biosynthetic routes: De novo and salvage pathways De novo pathways Almost all cell types have the ability to synthesize purine and pyrimidine nucleotides from low molecular weight precursors in amounts sufficient for their own needs. The de novo pathways are almost identical in all organisms. Salvage pathways Most organisms have the ability to synthesize nucleotides from nucleosides or bases that become available through the diet or from degredation of nucleic acids. In animals, the extracellular hydrolysis of ingested nucleic acids represents the major route by which bases become available. Reutilization and catabolism of purine and pyrimidine bases blue-catabolism red-salvage pathways endonucleases: pancreatic RNAse pancreatic DNAse phosphodiesterases: usually non-specific PRPP: a central metabolite in de novo and salvage pathways Roles of PRPP: his and trp biosynthesis, nucleobase salvage pathways, de novo synthesis of nucleotides PRPP synthetase Enzyme inhinited by AMP, ADP, and GDP. In E. coli , expression is repressed by PurR repressor bound to either guanine or hypoxanthine. Example of a salvage pathway: guanine phosphoribosyl transferase...
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This note was uploaded on 02/17/2012 for the course CHEM 212 taught by Professor Staff during the Fall '10 term at Rutgers.

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Nucleotide_metab_1 - Nucleotide Metabolism QuickTimeª and a GIF decompressor are needed to see this picture Roles of Nucleotides • Precursors to

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