Purine nucleotide synthesis is done from

With the exception of parasitic protozoa, all forms of life synthesize purine and pyrimidine nucleotides. Synthesis from amphibolic intermediates proceeds at controlled rates appropriate for all cellular functions. To achieve homeostasis, intracellular mechanisms sense and regulate the pool sizes of NTPs, which rise during growth or tissue regeneration when cells are rapidly dividing. Glycine is involved in second step of the reaction.Ref: Harpers Illustrated Biochemistry, 30th edition, page no: 348