Nucleotide salvage

A salvage pathway is a pathway in which nucleotides (purine and pyrimidine) are synthesized from intermediates in the degradative pathway for nucleotides.

Salvage pathways are used to recover bases and nucleosides that are formed during degradation of RNA and DNA.

The salvaged bases and nucleosides can then be converted back into nucleotides.

Substrates
The salvage pathway requires distinct substrates:

Pyrimidines
Thymidine requires a substrate whose enzyme is called thymidine kinase

Purines
Lesch-Nyhan syndrome is associated with a deficiency of HGPRT.