Metabolic pathway
Salvage pathway
Rescues the bases that are freed when nucleotides break down and puts them back to use in a single step. It is much cheaper than making them anew, and nervous tissue depends on it almost entirely.
- In
- Hypoxanthine + PRPP + NAD⁺ + 2 Water + Glutamine + ATP
- Out
- GMP + 2 Pyrophosphate + NADH + Proton + Glutamate + AMP
- Location
- Cytosol
Fun facts
- Hypoxanthine-guanine phosphoribosyltransferaseIts complete absence causes Lesch-Nyhan syndrome. Without it the bases are not recycled, they are broken down to uric acid and build up; and for reasons that are still not fully understood, the main damage is not to the joints but neurological.
Reactions
| # | Enzyme | ΔG°′ |
|---|---|---|
| 1 | Hypoxanthine-guanine phosphoribosyltransferaseEC 2.4.2.8 · irreversibleHypoxanthine + PRPP → IMP + Pyrophosphate | — |
| 2 | IMP dehydrogenaseEC 1.1.1.205 · irreversibleIMP + NAD⁺ + Water → XMP + NADH + Proton | — |
| 3 | GMP synthaseEC 6.3.5.2 · irreversibleXMP + Glutamine + ATP + Water → GMP + Glutamate + AMP + Pyrophosphate | — |
0 of 3 reactions with a documented ΔG.
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The data sheet includes the map. The logo goes at the bottom.
Sources
- Nelson, D. L. & Cox, M. M. (2021). Lehninger. Principios de bioquímica, 8.ª ed., ch. 22