Display Settings:


Send to:

Choose Destination

superpathway of adenosine nucleotides de novo biosynthesis II

General Background De novo biosynthesis of purines starts with the synthesis of IMP which can be converted to all other purines. In E. coli IMP is synthesized in a total of 11 enzymatic reactions in which the purine ring is formed by stepwise addition of small molecules to 5-phospho-alpha-D-ribose-1-phosphate (PRPP). The first five reactions are shown in pathways : PWY-6121 and : PWY-6122 which illustrate the alternative use of two phosphoribosylglycinamide formyltransferases encoded by purN and purT. The last six reactions leading to IMP are shown in pathway : PWY-6123. IMP can then be converted to guanosine nucleotides as shown in pathway : PWY-6125, or adenosine nucleotides as shown in this pathway. About This Pathway IMP is converted to adenylo-succinate by the enzyme : ADENYLOSUCCINATE-SYN-DIMER (PurA) and the latter compound is converted to the first adenosine nucleotide, AMP, by the : AMPSYN-ENZRXN activity of PurB. AMP is then converted to ADP and subsequently to ATP. The AMP to ADP conversion is catalyzed by : ADENYL-KIN-MONOMER, a specific nucleoside monophosphate kinase. Numerous reactions can convert ADP to ATP and they can be found in multiple pathways including fueling pathways such as anaerobic respiration, TCA-aerobic respiration, fermentation, and glycolysis. However, a major source for this conversion is the : ATPSYN-CPLX complex, which is membrane bound and utilizes a proton gradient across membranes to phosphorylate ADP. This is the reaction depicted in this pathway. ADP can also be converted to the deoxy form dADP by either : RIBONUCLEOSIDE-DIP-REDUCTI-CPLX (NrdAB) or : RIBONUCLEOSIDE-DIP-REDUCTII-CPLX (NrdEF). dADP is converted to dATP by : NUCLEOSIDE-DIP-KIN-CPLX (Ndk). Under strictly anaerobic conditions, the : ENZRXN0-805 activity of the class III ribonucleotide reductase NrdD can convert ATP to its deoxy form. In bacteria, genetic studies have indicated that the majority of de novo purine biosynthetic genes are unlinked, but may act as a single unit of regulation controlled by the PurR repressor protein . Review: Jensen, K.F., G. Dandanell, B. Hove-Jensen, and M. Willemoes (2008) "Nucleotides, Nucleosides and Nucleobases" EcoSal 3.6.2

from BIOCYC source record: ECO_PWY-6126
Type: pathway
Taxonomic scope
organism-specific biosystem
Escherichia coli

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Support Center