This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: adenosine ribonucleotide/ribonucleoside metabolism
|Superclasses:||Degradation/Utilization/Assimilation → Nucleosides and Nucleotides Degradation → Purine Nucleotides Degradation → Adenosine Nucleotides Degradation|
Expected Taxonomic Range: Bacteria
The distinction between nucleoside degradation and salvage is not always straight forward. A general rule is that degradation pathways start with the nucleotide forms and convert them to simpler forms, eventually leading to complete mineralization, while salvage pathways start with either the nucleoside or the free base form, and convert those to the nucleotide forms.
Nucleotide recycling is achieved by a combination of both types - a nucleotide is partially degraded via a degradation pathway, but the products are shuttled into a salvage pathway rather then towrds complete mineralization.
About This Pathway
The pathway that is described here is a degradation pathway found in some bacteria, that typically feeds into a salvage pathway. In Escherichia coli K-12 this is the major route of AMP catabolism. AMP degradation is not used necessarily for energy production, but is often required for maintaining the ATP to AMP ratio at relatively constant levels in the face of declining absolute levels of ATP. Thus partial degradation of AMP to a product that can be recycled to the nucleotide later is desired.
The enzyme AMP nucleosidase (EC 18.104.22.168 Can convert AMP into adenine in a single step [Leung80]. The adenine that is produced in the nucleosidase reaction can be reincorporated into the purine pool via the salvage pathways [Leung80, Leung89].
Unification Links: EcoCyc:PWY-6617
Leung89: Leung HB, Kvalnes-Krick KL, Meyer SL, deRiel JK, Schramm VL (1989). "Structure and regulation of the AMP nucleosidase gene (amn) from Escherichia coli." Biochemistry 1989;28(22);8726-33. PMID: 2690948
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Giranda89: Giranda VL, Berman HM, Schramm VL (1989). "Crystallographic quaternary structural analysis of AMP nucleosidases from Escherichia coli and Azotobacter vinelandii." J Biol Chem 264(26);15674-80. PMID: 2670945
KvalnesKrick93: Kvalnes-Krick K, Labdon JE, Ma X, Nieves E, Schramm VL (1993). "Mutagenic analysis of AMP nucleosidase from Escherichia coli. Deletion of a region similar to AMP deaminase and peptide characterization by mass spectrometry." J Biol Chem 268(12);8717-26. PMID: 8473316
Parkin87: Parkin DW, Schramm VL (1987). "Catalytic and allosteric mechanism of AMP nucleosidase from primary, beta-secondary, and multiple heavy atom kinetic isotope effects." Biochemistry 26(3);913-20. PMID: 3552037
Parkin91: Parkin DW, Mentch F, Banks GA, Horenstein BA, Schramm VL (1991). "Transition-state analysis of a Vmax mutant of AMP nucleosidase by the application of heavy-atom kinetic isotope effects." Biochemistry 30(18);4586-94. PMID: 2021651
Parry11: Parry BR, Shain DH (2011). "Manipulations of AMP metabolic genes increase growth rate and cold tolerance in Escherichia coli: implications for psychrophilic evolution." Mol Biol Evol 28(7);2139-45. PMID: 21300985
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