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
20. 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-phosphoribosy lamine A glycine(2C+IN), a Nio-formyl H4 folate(1C),aGIn INy, a HCO3 (C)Asp(IN), and another N1o-formyl H4 folate (1c) then brings the rest atoms for the purine ring
20. 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 (inosinate).k 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 (inosinate). • 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
The purine ring is built up one or a few atoms at a time on ribose 5-P ①O-CH2O H HH 5-Phosphoribosyl HC OH OH I-pyrophosphate(PRPP) C-H Formyldycinamide O=C ribonucleotide(FGAR) Glutamine NH → Glutamate Glutamine ①OCH2O Glutamate NI H o-Phospho-B- ATP D-ribosylamine →ADP+P OH OH Glvcine H C-HFormylglycinamidine HN=C ribonucleotide (FGAM) ATP N →ADP+P1 Steps 1.3, and 5 are R NH3 catalyzed by one HC Glycinamide O(ADP+P. multifunctional protein O=C ribonucleotide(GAR) GHo in some eukaryotic cells. R H 5-Aminoimidazole N° FormvI H4 folate ribonucleotide (AIR) H2N Ha folate
The purine ring is built up one or a few atoms at a time on ribose 5-P Steps 1, 3, and 5 are catalyzed by one multifunctional protein in some eukaryotic cells