CO2 Glycine Aspartate C N C ‖C← Formate C C Formate N个A N↑N mide of glutamine Radioisotope tracer experiments revealed the origins of the ring atoms of purines
Radioisotope tracer experiments revealed the origins of the ring atoms of purines
From carbamoyl From GIn amide phosphate aspartate C NA4C 3 5 2,6c HCO3 The atoms of the pyrimidine rings were revealed to Be derived from HCO3, GIn and Asp
Gln amide HCO3 - C The atoms of the pyrimidine rings were revealed to Be derived from HCO3 - , Gln and Asp
3. De novo purine nucleotide synthesis begins with the transferring of an amino group from GIn to PRPP PRPP is synthesized from ribose 5-P In the first(committing step of purine nucleotide synthesis, the Ppi part on PRPp (at C-1)is replaced by the side chain amino group of gIn forming 5-phosphoribosylamine a glycine(2C +lN), a Ni0-formyl H4 folate(1C),a GIn(IN),a HCO3(1C)Asp(1N),and another N10 formyl H4 folate(1c then brings the rest atoms for the purine ring
3. De novo purine nucleotide synthesis begins with the transferring of an amino group from Gln to PRPP • PRPP is synthesized from ribose 5-P. • In the first (committing) step of purine nucleotide synthesis, the PPi part on PRPP (at C-1) is replaced by the side chain amino group of Gln, forming 5-phosphoribosylamine. • A glycine (2C +1N), a N10-formyl H4 folate (1C), a Gln (1N), a HCO3 - (1C) Asp (1N), and another N10- formyl H4 folate (1C) then brings the rest atoms for the purine ring
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
0 0—PocH2O、H MP_O—POCH,O、H HH OH PRPP synthetase H 0-P-0-P-0 HO OH HO OH O Ribose 5-phosphate 5-Phosphoribosyl-1-pyrophosphate (PRPP) PRPP is synthesized from ribose 5-P in a Reaction catalyzed by prpp synthetase
PRPP is synthesized from ribose 5-P in a Reaction catalyzed by PRPP synthetase