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: purine ribonucleotide/ribonucleoside metabolism
|Superclasses:||Degradation/Utilization/Assimilation → Nucleosides and Nucleotides Degradation → Purine Nucleotides Degradation → Adenosine Nucleotides Degradation|
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
This pathway shares several steps with the pathway adenine and adenosine salvage III. However, the salvage pathway starts with the free base adenine (which is often transported into the organism) and ends with the nucleotide IMP, leading to biosynthesis of nucleotides, while this degradation pathway starts with the nucleotide form (AMP) and ends with urate, which in most organisms is degraded further, providing the organism with carbon, nitrogen and energy.
A key enzyme in this pathway is adenosine deaminase, which converts adenosine to inosine. This has been shown to be the main form of adenosine degradation by the fungi Aspergillus terricola [Elshafei95] and Penicillium palitans [Elshafei05].
Xanthine degradation to allantoin has been observed in Escherichia coli, but this degradation does not progress past allantoin or allantoate and this catabolism does not suffice as a source of nitrogen under aerobic growth conditions [Xi00].
Superpathways: purine nucleotides degradation II (aerobic)
Unification Links: EcoCyc:SALVADEHYPOX-PWY
Elshafei95: Elshafei AM, Abu-Shady MR, el-Beih FM, Mohamed LA (1995). "Mode and extent of degradation of adenosine and guanosine by extracts of Aspergillus terricola." Microbiol Res 150(3);291-5. PMID: 7551735
AlvesPereira08: Alves-Pereira I, Canales J, Cabezas A, Cordero PM, Costas MJ, Cameselle JC (2008). "CDP-alcohol hydrolase, a very efficient activity of the 5'-nucleotidase/UDP-sugar hydrolase encoded by the ushA gene of Yersinia intermedia and Escherichia coli." J Bacteriol 190(18);6153-61. PMID: 18641143
Amaya02: Amaya Y, Kawamoto S, Kashima Y, Okamoto K, Nishino T (2002). "Purification and characterization of multiple forms of rat liver xanthine oxidoreductase expressed in baculovirus-insect cell system." J Biochem 132(4);597-606. PMID: 12359075
Amaya90: Amaya Y, Yamazaki K, Sato M, Noda K, Nishino T (1990). "Proteolytic conversion of xanthine dehydrogenase from the NAD-dependent type to the O2-dependent type. Amino acid sequence of rat liver xanthine dehydrogenase and identification of the cleavage sites of the enzyme protein during irreversible conversion by trypsin." J Biol Chem 265(24);14170-5. PMID: 2387845
Asai07: Asai R, Matsumura T, Okamoto K, Igarashi K, Pai EF, Nishino T (2007). "Two mutations convert mammalian xanthine oxidoreductase to highly superoxide-productive xanthine oxidase." J Biochem 141(4);525-34. PMID: 17301076
Bennett03: Bennett EM, Li C, Allan PW, Parker WB, Ealick SE (2003). "Structural basis for substrate specificity of Escherichia coli purine nucleoside phosphorylase." J Biol Chem 278(47);47110-8. PMID: 12937174
Bennett03a: Bennett EM, Anand R, Allan PW, Hassan AE, Hong JS, Levasseur DN, McPherson DT, Parker WB, Secrist JA, Sorscher EJ, Townes TM, Waud WR, Ealick SE (2003). "Designer gene therapy using an Escherichia coli purine nucleoside phosphorylase/prodrug system." Chem Biol 10(12);1173-81. PMID: 14700625
Bertoša14: Bertosa B, Mikleusevic G, Wielgus-Kutrowska B, Narczyk M, Hajnic M, Lescic Asler I, Tomic S, Luic M, Bzowska A (2014). "Homooligomerization is needed for stability: a molecular modelling and solution study of Escherichia coli purine nucleoside phosphorylase." FEBS J 281(7);1860-71. PMID: 24785777
Bezirdzhian86: Bezirdzhian KhO, Kocharian ShM, Akopian ZhI (1986). "[Isolation of the hexameric form of purine nucleoside phosphorylase from E. coli. Comparative study of trimeric and hexameric forms of the enzyme]." Biokhimiia 1986;51(7);1085-92. PMID: 3089333
Bezirdzhian87: Bezirdzhian KhO, Kocharian ShM, Akopian ZhI (1987). "[Hexameric purine nucleoside phosphorylase II from Escherichia coli K-12. Physico-chemical and catalytic properties and stabilization with substrates]." Biokhimiia 1987;52(10);1624-31. PMID: 3122852
Bezirdzhian87a: Bezirdzhian KhO, Kocharian ShM, Akopian ZhI (1987). "[Hexamere purine nucleoside phosphorylase from Escherichia coli K-12. Kinetic analysis and mechanism of reaction]." Biokhimiia 52(11);1770-6. PMID: 3125860
Bonthron85: Bonthron DT, Markham AF, Ginsburg D, Orkin SH (1985). "Identification of a point mutation in the adenosine deaminase gene responsible for immunodeficiency." J Clin Invest 76(2);894-7. PMID: 3839802
Borowiec06: Borowiec A, Lechward K, Tkacz-Stachowska K, Skladanowski AC (2006). "Adenosine as a metabolic regulator of tissue function: production of adenosine by cytoplasmic 5'-nucleotidases." Acta Biochim Pol 53(2);269-78. PMID: 16770441
Bradshaw81: Bradshaw RA, Cancedda F, Ericsson LH, Neumann PA, Piccoli SP, Schlesinger MJ, Shriefer K, Walsh KA (1981). "Amino acid sequence of Escherichia coli alkaline phosphatase." Proc Natl Acad Sci U S A 1981;78(6);3473-7. PMID: 7022451
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