USMLE

Purine Salvage

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Biochemical Pathways
  1. Glycolysis
  2. Citric Acid Cycle (TCA Cycle)
  3. Electron Transport Chain (ETC)
  4. Cori Cycle
  5. De Novo Purine Synthesis
  6. De Novo Pyrimidine Synthesis
  7. Purine Salvage
  8. Purine Excretion
  9. Ethanol Metabolism
  10. Pyruvate Metabolism
  11. HMP Shunt (Pentose Phosphate Pathway)
  12. Galactose Metabolism
  13. Sorbitol (Polyol) Pathway
  14. Urea Cycle
  15. Alanine (Cahill) Cycle
  16. Catecholamine Synthesis & Breakdown
  17. Homocysteine Metabolism
  18. Fatty Acid Synthesis (Citrate Shuttle)
  19. Fatty Acid Breakdown (Carnitine Shuttle)
  20. Propionic Acid Pathway
  21. Fructose Metabolism
  22. Regulation by Fructose-2,6-Bisphosphate (F-2,6-BP)
  23. Glycogenesis

Purine Salvage is a biochemical pathway that recycles partially degraded purine bases to reform purine nucleotides.

Purine salvage begins with the free nitrogenous bases, hypoxanthine and guanine. Guanine combines with PRPP to form GMP, whereas Hypoxanthine combines with PRPP to form IMP. IMP can then be interconverted with AMP. Therefore, salvage of AMP occurs through hypoxanthine.

Both salvage reactions with PRPP are catalyzed by HGPRT (hypoxanthine guanine phosphoribosyltransferase). Notably, Lesch-Nyhan Syndrome is caused by a defect of HGPRT and impairs purine salvage.

A less common purine salvage pathway begins with adenine, since adenine is not usually produced by purine degradation. Adenine combines with PRPP to form AMP, in a reaction catalyzed by APRT (adenine phosphoribosyltransferase).

Find Purine Salvage and more Biochemical Pathways among Pixorize's visual mnemonics for the USMLE Step 1 and NBME Shelf Exams.