MetaCyc Pathway: guanine and guanosine salvage III
Inferred from experiment

Enzyme View:

Pathway diagram: guanine and guanosine salvage III

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.

Superclasses: BiosynthesisNucleosides and Nucleotides BiosynthesisPurine Nucleotide BiosynthesisPurine Nucleotide SalvageGuanine and Guanosine Salvage

Some taxa known to possess this pathway include : Escherichia coli K-12 substr. MG1655, Helianthus tuberosus, Mycoplasma pneumoniae M129

Expected Taxonomic Range: Archaea, Bacteria , Viridiplantae

Guanosine nucleotides can be synthesized de novo. In that route GMP (GMP) is synthesized via IMP (IMP) and XMP (XMP) , which is converted to GMP by the action of GMP synthetase, an enzyme that can use either glutamine or ammonia as substrate (see superpathway of guanosine nucleotides de novo biosynthesis II). Note that the free base guanine or the ribonucleoside guanosine are not produced via the de novo pathway.

Many organisms can also recycle guanosine nucleotides by a combination of degradation and salvage pathways. The degradation pathway is responsible for the degradation of the nucleotides to the nucleoside guanosine and the base guanine, which can be further degraded via xanthine and urate, and eventually catabolized to basic building blocks (see superpathway of guanosine nucleotides degradation (plants)).

However, both guanosine and guanine can be salvaged by certain enzymes, and be converted back to nucleotide form.

The enzyme inosine-guanosine kinase (EC, which has been studied in Escherichia coli, can phosphorylate guanosine directly to the mono-nucleotide GMP. Even though genes encoding this enzyme have been identified only in bacteria and archaea [Kawasaki00], this activity has also been reported for artichoke, Helianthus tuberosus [Combes89].

Other routes from guanosine to GMP are described in guanine and guanosine salvage and guanine and guanosine salvage II.

Either of these routes enables the organism to salvage the degradation products of guanosine nucleotides, and recycle them back to nucleotide form.

Superpathways: superpathway of guanine and guanosine salvage

Variants: guanine and guanosine salvage, guanine and guanosine salvage II

Unification Links: EcoCyc:PWY-6618

Created 27-Sep-2010 by Caspi R, SRI International


Combes89: Combes, Agnes, Lafleuriel, Jacqueline, Le Floc'h, Francois (1989). "The inosine-guanosine kinase activity of mitochondria in tubers of Jerusalem artichoke." Plant Physiol. Biochem. 27(5):729-736.

Kawasaki00: Kawasaki H, Shimaoka M, Usuda Y, Utagawa T (2000). "End-product regulation and kinetic mechanism of guanosine-inosine kinase from Escherichia coli." Biosci Biotechnol Biochem 2000;64(5);972-9. PMID: 10879466

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Butland05: Butland G, Peregrin-Alvarez JM, Li J, Yang W, Yang X, Canadien V, Starostine A, Richards D, Beattie B, Krogan N, Davey M, Parkinson J, Greenblatt J, Emili A (2005). "Interaction network containing conserved and essential protein complexes in Escherichia coli." Nature 433(7025);531-7. PMID: 15690043

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

GOA01: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

GOA01a: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

Harlow95: Harlow KW, Nygaard P, Hove-Jensen B (1995). "Cloning and characterization of the gsk gene encoding guanosine kinase of Escherichia coli." J Bacteriol 177(8);2236-40. PMID: 7721718

HoveJensen89: Hove-Jensen B, Nygaard P (1989). "Role of guanosine kinase in the utilization of guanosine for nucleotide synthesis in Escherichia coli." J Gen Microbiol 135(5);1263-73. PMID: 2559948

Jochimsen75: Jochimsen B, Nygaard P, Vestergaard T (1975). "Location on the chromosome of Escherichia coli of genes governing purine metabolism. Adenosine deaminase (add), guanosine kinase (gsk) and hypoxanthine phosphoribosyltransferase (hpt)." Mol Gen Genet 1975;143(1);85-91. PMID: 765747

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Matsui01: Matsui H, Shimaoka M, Takenaka Y, Kawasaki H, Kurahashi O (2001). "gsk disruption leads to guanosine accumulation in Escherichia coli." Biosci Biotechnol Biochem 65(5);1230-5. PMID: 11440147

Mori95: Mori H, Iida A, Teshiba S, Fujio T (1995). "Cloning of a guanosine-inosine kinase gene of Escherichia coli and characterization of the purified gene product." J Bacteriol 177(17);4921-6. PMID: 7665468

Rajagopala14: Rajagopala SV, Sikorski P, Kumar A, Mosca R, Vlasblom J, Arnold R, Franca-Koh J, Pakala SB, Phanse S, Ceol A, Hauser R, Siszler G, Wuchty S, Emili A, Babu M, Aloy P, Pieper R, Uetz P (2014). "The binary protein-protein interaction landscape of Escherichia coli." Nat Biotechnol 32(3);285-90. PMID: 24561554

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA12: UniProt-GOA (2012). "Gene Ontology annotation based on UniPathway vocabulary mapping."

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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