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:||Biosynthesis → Nucleosides and Nucleotides Biosynthesis → Purine Nucleotide Biosynthesis → Purine Nucleotide Salvage → Guanine and Guanosine Salvage|
Many organisms can synthesize guanosine nucleotides 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 also use salvage enzymes to obtain purine bases and nucleosides and convert them to the corresponding nucleotides. The pathway described here is used by both prokaryotic and eukaryotic organisms for this purpose. For example, all parasitic protozoa (e.g.
The pathway has also been described in green plants [Guranowski79].
deKoning00: de Koning HP, Watson CJ, Sutcliffe L, Jarvis SM (2000). "Differential regulation of nucleoside and nucleobase transporters in Crithidia fasciculata and Trypanosoma brucei brucei." Mol Biochem Parasitol 106(1);93-107. PMID: 10743614
Deo85: Deo SS, Tseng WC, Saini R, Coles RS, Athwal RS (1985). "Purification and characterization of Escherichia coli xanthine-guanine phosphoribosyltransferase produced by plasmid pSV2gpt." Biochim Biophys Acta 839(3);233-9. PMID: 3886014
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
Free90: Free ML, Gordon RB, Keough DT, Beacham IR, Emmerson BT, de Jersey J (1990). "Expression of active human hypoxanthine-guanine phosphoribosyltransferase in Escherichia coli and characterisation of the recombinant enzyme." Biochim Biophys Acta 1087(2);205-11. PMID: 2223882
Guddat02: Guddat LW, Vos S, Martin JL, Keough DT, de Jersey J (2002). "Crystal structures of free, IMP-, and GMP-bound Escherichia coli hypoxanthine phosphoribosyltransferase." Protein Sci 11(7);1626-38. PMID: 12070315
Hirose84: Hirose, Fumiko, Ashihara, Hiroshi (1984). "Changes in the activity of enzymes involved in purine "salvage" and nucleic acid degrdation during the growth of Catharanthus roseus cells in suspension culture." Physiol. Plant. 60:532-538.
Liu83: Liu SW, Milman G (1983). "Purification and characterization of Escherichia coli guanine-xanthine phosphoribosyltransferase produced by a high efficiency expression plasmid utilizing a lambda PL promoter and CI857 temperature-sensitive repressor." J Biol Chem 1983;258(12);7469-75. PMID: 6305942
Nussbaum81: Nussbaum RL, Caskey CT (1981). "Purification and characterization of hypoxanthine-guanine phosphoribosyltransferase from Saccharomyces cerevisiae." Biochemistry 20(16);4584-90. PMID: 6170313
Schmidt79: Schmidt R, Wiegand H, Reichert U (1979). "Purification and characterization of the hypoxanthine-guanine phosphoribosyltransferase from Saccharomyces cerevisiae." Eur J Biochem 93(2);355-61. PMID: 371963
Versees01: Versees W, Decanniere K, Pelle R, Depoorter J, Brosens E, Parkin DW, Steyaert J (2001). "Structure and function of a novel purine specific nucleoside hydrolase from Trypanosoma vivax." J Mol Biol 307(5);1363-79. PMID: 11292348
Xu97: Xu Y, Eads J, Sacchettini JC, Grubmeyer C (1997). "Kinetic mechanism of human hypoxanthine-guanine phosphoribosyltransferase: rapid phosphoribosyl transfer chemistry." Biochemistry 36(12);3700-12. PMID: 9132023
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