De novo synthesis of purine nucleotide includes two major processes: (1)Synthesis from PRPP to IMP (2)Conversion of IMP to GMP and AMP. 。Major site:liver De novo synthesis of purine is weak in brain and erythrocyte
• De novo synthesis of purine nucleotide includes two major processes: (1) Synthesis from PRPP to IMP (2) Conversion of IMP to GMP and AMP. • Major site: liver • De novo synthesis of purine is weak in brain and erythrocyte
Overview of de novo pathway for synthesis of purine Glycine H-CE ⊙-0-c ⊙-o-cH ⊙-o-cH ATP H,oat 3 Mg ⊙-0-⊙ ANDOTHANSI MASE 4 OH OH OHOH OH OH OH a-D-Ribose 5-phosphate 5-Phospho-B-D-ribosylamin 0v) Key stepl Key step2 000 HC-NH VI SYNTHETASE⑤ Aspartate H.O CO. ⑥ IX SYNTHETASE VI CARBOXYLASE H.N VII SYNTHETASE Hd9 A5-@ R5 Fumarate 5-⊙ Aminoimidazole succinyl Aminoimidazole Aminoimidazole carboxamide ribosyl-5-phosphate carboxylate ribosyl-5-phosphate ribosyl-5-phosphate ribosyl-5-phosphate (v0 W (VD ADENYLOSUCCINASE Ha folate H.N o H N R5 IMP CYCLOHYDROLASE A-5® Aminoimidazole carboxamide Formimidoimidazole carboxamide Inosine monophosphate (IMP) nbosyl-5-phosphate ribosyl-5-phosphate (9 IMP
Overview of de novo pathway for synthesis of purine IMP Key step1 Key step2
(1)Synthesis from PRPP to IMP
(1) Synthesis from PRPP to IMP
1st step HC-0 H2C-0-P ATP AMP OH PRPP synthetase OH OH Key enzyme OH OH Ribose 5-phosphate Phosphoribosyl pyrophosphate (PRPP) The 1st step in the pathway is the synthesis of PRPP by PRPP synthetase.This step is regulated by feedback inhibition
1st step The 1st step in the pathway is the synthesis of PRPP by PRPP synthetase. This step is regulated by feedback inhibition. Key enzyme
Function of PRPP PRPP is the source of the ribose sugar and 5'phosphate found in purine nucleotides. 0 P-O-CH2 0- p-0-CH20、 guanine OH OH OHOH OHOH PRPP GMP
Function of PRPP PRPP is the source of the ribose sugar and 5’ phosphate found in purine nucleotides