Nucleotide Metabolism

Nucleotide Metabolism

• Nucleotides have various roles in cellular metabolism, including:
  • Precursors for DNA and RNA synthesis
  • Carriers of chemical energy (e.g., ATP, GTP)
  • Components of cofactors (NAD+, FAD, coenzyme A)
  • Carriers of active intermediates (e.g., UDP-glucose, CDP-diacylglycerol)
  • Cellular second messengers (e.g., cAMP, cGMP)
  • Allosteric regulation of metabolic pathways

de novo Synthesis of Nucleotides

• Purine nucleotide synthesis requires:
  • Undisclosed substrates (not mentioned in the text)
• Pyrimidine nucleotide synthesis requires:
  • Aspartate as a carbon and nitrogen donor
  • Glutamine as a nitrogen donor
  • CO2 as a carbon donor

Genetic Disorders of Nucleotide Metabolism

• Defects in pyrimidine nucleotide metabolism can lead to clinical disorders
• These disorders can present in various clinical situations, including:
  • Anemia
  • Neurological conditions

Purine Nucleotide Catabolism

• Purine nucleotide catabolism involves:
  • PNP (Purine Nucleoside Phosphorylase)
  • Allopurinol (a treatment for hyperuricemia and hyperuricuria)
• Gout is caused by:
  • Precipitation of sodium urate crystals in the joints
  • Inflammation and pain
• Gout is treated by:
  • Allopurinol

Ribonucleotides and Deoxyribonucleotides

• Ribonucleotides can be converted to deoxyribonucleotides via:
  • Ribonucleotide Reductase

Base Pairs in DNA and RNA

• Both DNA and RNA contain the same purine bases:
  • Adenine (A)
  • Guanine (G)
• Both DNA and RNA contain the pyrimidine:
  • Cytosine (C)
• DNA and RNA differ in their second pyrimidine base:
  • DNA contains thymine (T)
  • RNA contains uracil (U)
• Thymine (T) has a methyl group, whereas uracil (U) does not