The first intermediate having a complete purine ring is IMP(次黄嘌呤核苷酸) IMP is converted to amp by accepting an amino group from Asp and converted to GMP by a NAD+-dependent dehydrogenation reaction(at C-2)and an amino group transfer from gIn (catalyzed by an amidotransferase) The production of AMP from IMP requires GTP and the production of GMP from IMP requires atp• The first intermediate having a complete purine ring is IMP (次黄嘌呤核苷酸). • IMP is converted to AMP by accepting an amino group from Asp, and converted to GMP by a NAD+-dependent dehydrogenation reaction (at C-2) and an amino group transfer from Gln (catalyzed by an amidotransferase). • The production of AMP from IMP requires GTP, and the production of GMP from IMP requires ATP