Deoxyribonucleotide synthesis

These transcription factors activate genes that express the enzymes for purine and pyrimidine deoxyribonucleotide synthesis and DNA duplication. 

Purine Biosynthesis Is Regulated at Two Levels Pyrimidine Biosynthesis Is Regulated at the Level of Carbamoyl Aspartate Formation Deoxyribonucleotide Synthesis Is Regulated by Both Activators and Inhibitors... 

Deoxyribonucleotide Synthesis Is Regulated by Both Activators and Inhibitors... 

The manner in which the reduction of ribonucleotides to deoxyribonucleotides is regulated has been studied with reductases from relatively few species. The enzymes from E. coli and from Novikoff s rat liver tumor have a complex pattern of inhibition and activation (fig. 23.25). ATP activates the reduction of both CDP and UDP. As dTTP is formed by metabolism of both dCDP and dUDP, it activates GDP reduction, and as dGTP accumulates, it activates ADP reduction. Finally, accumulation of dATP causes inhibition of the reduction of all substrates. This regulation is reinforced by dGTP inhibition of the reduction of GDP, UDP, and CDP and by dTTP inhibition of the reduction of the pyrimidine substrates. Because evidence suggests that ribonucleotide reductase may be the rate-limiting step in deoxyribonucleotide synthesis in at least some animal cells, these allosteric effects may be important in controlling deoxyribonucleotide synthesis. 

Reichard P., Interactions between deoxyribonucleotide and DNA synthesis. Ann. Rev. Biochem. 57 349-374, 1988. Comprehensive review of deoxyribonucleotide synthesis and its relation to DNA synthesis. 

Non-haem enzymes Ribonucleotide reductase dinuclear iron deoxyribonucleotide synthesis Tyrosine 3.2.1. 

Synthesis of Thymidine nucleotides first requires deoxyribonucleotide synthesis. The enzyme responsible for this step is Ribonucleotide Reductase. This enzyme acts on oxynucleotides in their diphosphate form. Thioredoxin, a small protein, is oxidized as the 2 hydroxyl group on the ribose ring is reduced. Oxidized Thioredoxin (S-S) is then reduced by FADH2 and NADPH. The products are the respective deoxynucleotide diphosphates which are further phosphorylated and then used for DNA synthesis. 

Dark Reactions, 472 Decarboxylation, 433 Deoxy Sugars, 52 Deoxycoformycin, 385 Deoxyribonucleotide Synthesis, 384 Derived Lipids, 78 Derived Proteins, 151 Derived Sugars, 52 Disaccharides, 55 DNA, 117... 

See also De Novo Biosynthesis of Purine Nucleotides, Purine Degradation, Excessive Uric Acid in Purine Degradation, Salvage Routes to Deoxyribonucleotide Synthesis, Nucleotide Analogs in Selection... 

See also De Novo Biosynthesis of Purine Nucleotides, Salvage Routes to Deoxyribonucleotide Synthesis... 

See also Drug Design, Salvage Routes to Deoxyribonucleotide Synthesis, DNA Replication Overview (from Chapter 24), Eukaryotic DNA Polymerases (from Chapter 24), Retrovirus Replication (from Chapter 24)... 

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