• Common intermediate in synthesizing AMP and GMP
• Also called inosine monophosphate IMP
• AMP: replace ketone with amino group
• GMP: add another ketone and aminate that
• In each case, we are aminating the molecule so we can add to it
• AMP

Phosphate group: GTP

Amino group: Aspartate

Loss of fumarate

End with Adenylate (AMP)

IMP (inosinate) + GTP + Asp -> Adenylosuccinate + Pi + GDP

Adenylosuccinate -> Fumarate and adenylate (AMP)

• GMP

Phosphate group: ATP

Amino group: Ammonia grom glutamine source

Inosinate (IMP) + H2O + NAD+ -> NADH + H+ + Xanthylate

Xanthylate + ATP + Glu + H3N -> Guanylate (GMP)

Glu and H3N are from Gln + H2O