<prompt> Salvage pathway of purine nucleotide synthesis are used by all EXCEPT:LeukocytesLiverRBCBrain  <response>: Salvage pathway occurs in: Brain RBCs WBCs Bone marrow. Brain, RBCs, WBCs and bone marrow lack the enzyme PRPP Glutamyl Amidotransferase and depends on the exogenous purine nucleosides to form nucleotides. Liver is the major site for denovo purine nucleotide synthesis 5 ATPmolecules are required for de novo purine synthesis. Summary of steps of purine synthesis: Step Donor Added atom Product 1.- Activation of R-5-P ATP required PRPP 2.Glutamine N9 Rate limiting PRA 3.Glycine ATP required C4,5,N7 GAR 4.Methenyl-THFA C8 FGAR 5.Glutamine N3 ATP required FGAM 6.- Ring closure ATP required AIR 7.Carbon dioxide C6 ACAIR 8.Aspaic acid N1ATP required SAICAR 9.- Fumarate removed AICAR 10.Formyl-THFA C2 FAICAR 11.- Ring closure 