MetaCyc Enzyme: allantoate amidohydrolase

Gene: AAH Accession Number: AT4G20070 (MetaCyc)

Synonyms: At4g20070, AtAAH

Species: Arabidopsis thaliana col

Subunit composition of allantoate amidohydrolase = [AAH]2
         allantoate amidohydrolase monomer = AAH

The cDNA encoding allantoate amidohydrolase was isolated from Arabidopsis thaliana col. The enzyme was initially reported to catalyzes the conversion of allantoate to yield S-ureidoglycolate via a (-)-ureidoglycine [Todd06], but a later study showed that the enzyme catalyzes only the first part - conversion of allantoate to a (-)-ureidoglycine [Werner10]

The function of the gene was confirmed by complementation of Saccharomyces cerevisiae DAL2 mutants, blocked in allantoate degradation. Mutants with T-DNA insertions in AAH, the gene encoding the enzyme, showed normal growth on standard medium, but growth was completely blocked when the sole N source was allantoin. The enzyme was expressed in all tissues indicating a vital role in metabolism. It was proposed that the enzyme is involved in the purine salvage pathway through ureide biosynthesis and degradation [Todd06].

The gene was subsequently cloned, expressed in planta in the form of several StrepII-tagged variants, and highly purified from leaf extracts. The enzyme requires Mn2+ and exists as a homodimer [Werner08].

Molecular Weight of Polypeptide: 56.524 kD (from nucleotide sequence)

Unification Links: Entrez:NP_193740 , PhylomeDB:O49434 , Pride:O49434 , Protein Model Portal:O49434 , SMR:O49434 , String:3702.AT4G20070.1-P , TAIR:At4g20070 , UniProt:O49434

Relationship Links: InterPro:IN-FAMILY:IPR001261 , InterPro:IN-FAMILY:IPR002933 , InterPro:IN-FAMILY:IPR010158 , InterPro:IN-FAMILY:IPR011650 , Pfam:IN-FAMILY:PF01546 , Pfam:IN-FAMILY:PF07687 , Prosite:IN-FAMILY:PS00758

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 10-May-2006 by Foerster H , TAIR
Revised 07-Nov-2007 by Caspi R , SRI International

Enzymatic reaction of: allantoate amidohydrolase

EC Number:

allantoate + 2 H+ + H2O <=> S-ureidoglycine + ammonium + CO2

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: superpathway of allantoin degradation in plants , allantoin degradation to glyoxylate II , allantoin degradation to ureidoglycolate II (ammonia producing)

Citations: [Todd06]

Cofactors or Prosthetic Groups: Mn2+ [Werner08]


Todd06: Todd CD, Polacco JC (2006). "AtAAH encodes a protein with allantoate amidohydrolase activity from Arabidopsis thaliana." Planta 223(5);1108-13. PMID: 16496096

Werner08: Werner AK, Sparkes IA, Romeis T, Witte CP (2008). "Identification, biochemical characterization, and subcellular localization of allantoate amidohydrolases from Arabidopsis and soybean." Plant Physiol 146(2);418-30. PMID: 18065556

Werner10: Werner AK, Romeis T, Witte CP (2010). "Ureide catabolism in Arabidopsis thaliana and Escherichia coli." Nat Chem Biol 6(1);19-21. PMID: 19935661

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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 Fri Oct 9, 2015, BIOCYC11A.