InterPro domain: IPR014311

This entry describes guanine deaminase, which hydrolyses guanine to xanthine and ammonia, the first step to utilize guanine as a nitrogen source. Xanthine can then be converted to urate by xanthine dehydrogenase. This reaction also removes the guanine base from the pool and therefore can play a role in the regulation of cellular GTP and the guanylate nucleotide pool [ 1 , 2 , 3 ]. In some bacteria, the guanine deaminase gene is found near the xdhABC genes for xanthine dehydrogenase. Non-homologous forms of guanine deaminase also exist, as well as more distantly related homologues which are not included in this entry.

1. Identification, expression, and characterization of Escherichia coli guanine deaminase. J. Bacteriol. 182, 4658-60
2. Cloning and characterization of human guanine deaminase. Purification and partial amino acid sequence of the mouse protein. J. Biol. Chem. 274, 8175-80
3. Bacillus subtilis guanine deaminase is encoded by the yknA gene and is induced during growth with purines as the nitrogen source. Microbiology (Reading, Engl.) 146 Pt 12, 3061-9