This is circumvented by one of two strategies. Low doses can be given along with folate supplements to allow normal metabolism but not rapid growth. Nucleosides with different numbers of phosphates can be interconverted rapidly. B. Salvage pathways While the bases found in DNA and RNA are not synthesized in a free form, cells can use the free bases or nucleosides to form nucleotides. These are called salvage or scavenging reactions.
Some cells rely exclusively on salvage pathways.
For example, there is very little de novo synthesis in neurons, and many pathogenic protozoans have no apparent de novo systems. This makes these cells vulnerable to disturbances in the salvage pathways, forming the basis for strategies to eradicate some pathogens. Salvaging free bases requires PRPP again. Nucleotide metabolism and disease states. A. Chemotherapeutic agents and nucleotide synthesis 1.