Nitrogen-9 of purine ring is provided by ?
In de novo synthesis, purine ring is formed from variety of precursors is assembled on ribose-5-phosphate. Precursors for de novo synthesis are - i) Glycine provides C4, C5 and N7 ii) Aspaate provides N1 iii) Glutamine provides N3 and N9 iv) Tetrahydrofolate derivatives furnish C2 and C8 v) Carbon dioxide provides C6
Glycine
Aspaate
Glutamine
CO2