MetaCyc Enzyme: guanine deaminase

Gene: GDA Accession Number: G-11616 (MetaCyc)

Synonyms: KIAA1258

Species: Homo sapiens

Subunit composition of guanine deaminase = [GDA]2
         guanine deaminase subunit = GDA

The native apparent molecular mass was determined by gel filtration chromatography [Gupta85].

Native human liver enzyme has been purified and characterized [Gupta85, Ito90a]. Recombinant enzyme has also been expressed in Escherichia coli, purified and characterized. Mn2+ stimulated the activity of the recombinant enzyme approximately 2-fold. Although no Mn2+ was found to be bound to the recombinant enzyme, the monomers contained Zn2+ [Yuan99].

This enzyme is present mainly in human liver, brain and kidney. It has been immunohistochemically localized in the cytoplasm of hepatocytes, small intestine mucosal epithelium and kidney proximal tubules [Kubo06]. Evidence for two isozymes was obtained during purification of the enzyme at the HPLC ion exchange chromatography step [Ito90a].
The subunit apparent molecular mass was determined by SDS-PAGE [Gupta85].

Locations: cytoplasm

Map Position: [74,764,293 -> 74,867,140]

Molecular Weight of Polypeptide: 51.003 kD (from nucleotide sequence), 59.0 kD (experimental) [Gupta85 ]

Molecular Weight of Multimer: 120.0 kD (experimental) [Gupta85]

pI: 4.76 [Gupta85]

Unification Links: ArrayExpress:Q9Y2T3 , Entrez-gene:9615 , Mint:MINT-109340 , PhosphoSite:Q9Y2T3 , PhylomeDB:Q9Y2T3 , Pride:Q9Y2T3 , Protein Model Portal:Q9Y2T3 , SMR:Q9Y2T3 , String:9606.ENSP00000351170 , UniProt:Q9Y2T3

Relationship Links: InterPro:IN-FAMILY:IPR006680 , InterPro:IN-FAMILY:IPR014311 , Panther:IN-FAMILY:PTHR11271:SF6 , PDB:Structure:2UZ9 , PDB:Structure:3E0L , PDB:Structure:4AQL , Pfam:IN-FAMILY:PF01979

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

GO Terms:

Cellular Component: GO:0005737 - cytoplasm [Kubo06]

Created 21-Oct-2009 by Fulcher CA , SRI International

Enzymatic reaction of: ammeline deaminase (guanine deaminase)

ammeline + H2O <=> ammelide + ammonium

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

The purified enzyme was shown to possess an ammeline deaminase activity of 57 nmol per min per mg [Seffernick10].

Enzymatic reaction of: guanine deaminase

Synonyms: guanase, guanine aminase

EC Number:

guanine + H+ + H2O <=> ammonium + xanthine

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

The reaction is physiologically favored in the direction shown. [Yuan99]

Alternative Substrates for guanine: azaguanine [Gupta85 ]

In Pathways: purine nucleotides degradation II (aerobic) , guanosine nucleotides degradation III

In mammals this enzyme reaction of purine catabolism is considered to be physiologically irreversible in the left to right direction. The production of xanthine and ammonia prevent reutilization of the guanine base (in [Yuan99]).

The apparent Km for guanine was determined at pH 6.0. iodoacetate was a weaker inhibitor of the enzyme than p-hydroxymercuribenzoate [Gupta85].

The pH optimum of the recombinant enzyme was 7.0 and the Km for guanine was 9.5 μM [Yuan99].

Cofactors or Prosthetic Groups: Zn2+ [Yuan99]

Activators (Unknown Mechanism): Mn2+ [Yuan99]

Inhibitors (Competitive): 5-amino-4-imidazolecarboxyamide [Gupta85]

Inhibitors (Noncompetitive): p-hydroxymercuribenzoate [Gupta85]

Kinetic Parameters:

Km (μM)

pH(opt): 8.0 [Gupta85]


Gupta85: Gupta NK, Glantz MD (1985). "Isolation and characterization of human liver guanine deaminase." Arch Biochem Biophys 236(1);266-76. PMID: 3966794

Ito90a: Ito S, Iwasaki A, Mizobuchi M, Matsuda Y (1990). "Purification of human liver guanase and characterization of antibody against it by immunoblotting." Clin Biochem 23(2);113-20. PMID: 2372926

Kubo06: Kubo K, Honda H, Sannomiya K, Aying Y, Mei W, Mi S, Aoyagi E, Simizu I, Ii K, Ito S (2006). "Histochemical and immunohistochemical investigation of guanase and nedasin in human tissues." J Med Invest 53(3-4);264-70. PMID: 16953063

Seffernick10: Seffernick JL, Dodge AG, Sadowsky MJ, Bumpus JA, Wackett LP (2010). "Bacterial ammeline metabolism via guanine deaminase." J Bacteriol 192:1106-12. PMID: 20023034

Yuan99: Yuan G, Bin JC, McKay DJ, Snyder FF (1999). "Cloning and characterization of human guanine deaminase. Purification and partial amino acid sequence of the mouse protein." J Biol Chem 274(12);8175-80. PMID: 10075721

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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
Page generated by SRI International Pathway Tools version 19.0 on Tue Jul 28, 2015, biocyc14.