Guanine deaminase

GDA
Identifiers
Aliases	GDA, guanine deaminase, CYPIN, GUANASE, NEDASIN, Guanine deaminase, GAH
External IDs	OMIM: 139260; MGI: 95678; GeneCards: GDA
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	4AQL, 3E0L, 2UZ9
Enzyme activity
Gene location (Human)
Chr.	Chromosome 9 (human)
End	72,257,193 bp
Gene location (Mouse)
Chr.	Chromosome 19 (mouse)
End	21,450,809 bp
RNA expression pattern
	Top expressed in
	mucosa of ileum; ; jejunal mucosa; ; pancreatic ductal cell; ; endothelial cell; ; Brodmann area 46; ; Brodmann area 23; ; middle temporal gyrus; ; entorhinal cortex; ; superior frontal gyrus; ; parietal lobe;
	Top expressed in
	epithelium of small intestine; ; ventromedial nucleus; ; granulocyte; ; subiculum; ; olfactory tubercle; ; anterior amygdaloid area; ; conjunctival fornix; ; nucleus accumbens; ; piriform cortex; ; lateral septal nucleus;
	More reference expression data
	n/a
Gene ontology
Molecular function	hydrolase activity; metal ion binding; hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds; zinc ion binding; guanine deaminase activity; protein binding;
Cellular component	cytosol; intracellular anatomical structure;
Biological process	guanine catabolic process; purine nucleotide catabolic process; nucleobase-containing compound metabolic process; nervous system development; guanine metabolic process;
	Sources:Amigo / QuickGO
Orthologs
Databases	NCBI: entry; OMA: entry
	9615
	14544
	ENSG00000119125
	ENSMUSG00000058624
	Q9Y2T3
	Q9R111
NM_001242505; NM_001242506; NM_001242507; NM_004293; NM_001351571;
	NM_001351572; NM_001351573
	NM_010266
NP_001229434; NP_001229435; NP_001229436; NP_004284; NP_001338500;
	NP_001338501; NP_001338502
	NP_034396
	Wikidata
View/Edit Human	View/Edit Mouse

Guanine deaminase also known as cypin, guanase, guanine aminase, GAH, and guanine aminohydrolase is an aminohydrolase enzyme first characterised from Girella nigricans which converts the nucleotide base, guanine, to xanthine and ammonia.

guanine

H₂O

NH₃

Rightward reaction arrow with minor substrate(s) from top left and minor product(s) to top right

xanthine

The aminohydrolase family of enzymes includes over 100,000 members and most have a TIM barrel fold. Cypin is found in all organisms as part of purine metabolism and uses a zinc cation to activate water for the hydrolysis. it is a major cytosolic protein that interacts with PSD-95. It promotes localized microtubule assembly in neuronal dendrites.

References

1 2 3 GRCh38: Ensembl release 89: ENSG00000119125 – Ensembl, May 2017
1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000058624 – Ensembl, May 2017
↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
↑ Hitchings GH, Falco EA (October 1944). "The Identification of Guanine in Extracts of Girella Nigricans: The Specificity of Guanase". Proceedings of the National Academy of Sciences of the United States of America. 30 (10): 294–297. Bibcode:1944PNAS...30..294H. doi:10.1073/pnas.30.10.294. PMC 1078714. PMID 16578130.
↑ Kalckar HM (1947). "Differential spectrophotometry of purine compounds by means of specific enzymes; studies of the enzymes of purine metabolism". The Journal of Biological Chemistry. 167 (2): 461–475. doi:10.1016/S0021-9258(17)30999-7. PMID 20285041.
↑ Rabinowitz JC, Barker HA (January 1956). "Purine fermentation by Clostridium cylindrosporum. II. Purine transformations". The Journal of Biological Chemistry. 218 (1): 161–173. doi:10.1016/S0021-9258(18)65881-8. PMID 13278325.
↑ Shek R, Hilaire T, Sim J, French JB (July 2019). "Structural Determinants for Substrate Selectivity in Guanine Deaminase Enzymes of the Amidohydrolase Superfamily". Biochemistry. 58 (30): 3280–3292. doi:10.1021/acs.biochem.9b00341. PMC 6677139. PMID 31283204.
↑ Ouyang Z, You K, Mi M, Lin Y, Zheng S (September 2025). "Microbial Production of Purine Nucleotides, Nucleosides, and Nucleobases: Advances and Perspectives". Biotechnology Journal. 20 (9) e70115. doi:10.1002/biot.70115. PMID 40899422.
↑ Firestein BL, Firestein BL, Brenman JE, Aoki C, Sanchez-Perez AM, El-Husseini AE, et al. (1999). "Cypin: a cytosolic regulator of PSD-95 postsynaptic targeting". Neuron. 24 (3): 659–672. doi:10.1016/S0896-6273(00)81120-4. PMID 10595517.

External links

Guanine+deaminase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Overview of all the structural information available in the PDB for UniProt: Q9Y2T3 (Human Guanine deaminase) at the PDBe-KB.

[refGRCh38Ensembl-1] 1 2 3 GRCh38: Ensembl release 89: ENSG00000119125 – Ensembl, May 2017

[refGRCm38Ensembl-2] 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000058624 – Ensembl, May 2017

[3] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[4] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[5] Hitchings GH, Falco EA (October 1944). "The Identification of Guanine in Extracts of Girella Nigricans: The Specificity of Guanase". Proceedings of the National Academy of Sciences of the United States of America. 30 (10): 294–297. Bibcode:1944PNAS...30..294H. doi:10.1073/pnas.30.10.294. PMC 1078714. PMID 16578130.

[Kalckar_1947-6] Kalckar HM (1947). "Differential spectrophotometry of purine compounds by means of specific enzymes; studies of the enzymes of purine metabolism". The Journal of Biological Chemistry. 167 (2): 461–475. doi:10.1016/S0021-9258(17)30999-7. PMID 20285041.

[7] Rabinowitz JC, Barker HA (January 1956). "Purine fermentation by Clostridium cylindrosporum. II. Purine transformations". The Journal of Biological Chemistry. 218 (1): 161–173. doi:10.1016/S0021-9258(18)65881-8. PMID 13278325.

[8] Shek R, Hilaire T, Sim J, French JB (July 2019). "Structural Determinants for Substrate Selectivity in Guanine Deaminase Enzymes of the Amidohydrolase Superfamily". Biochemistry. 58 (30): 3280–3292. doi:10.1021/acs.biochem.9b00341. PMC 6677139. PMID 31283204.

[9] Ouyang Z, You K, Mi M, Lin Y, Zheng S (September 2025). "Microbial Production of Purine Nucleotides, Nucleosides, and Nucleobases: Advances and Perspectives". Biotechnology Journal. 20 (9) e70115. doi:10.1002/biot.70115. PMID 40899422.

[Firestein_1999-10] Firestein BL, Firestein BL, Brenman JE, Aoki C, Sanchez-Perez AM, El-Husseini AE, et al. (1999). "Cypin: a cytosolic regulator of PSD-95 postsynaptic targeting". Neuron. 24 (3): 659–672. doi:10.1016/S0896-6273(00)81120-4. PMID 10595517.

v t e Hydrolases: carbon-nitrogen non-peptide (EC 3.5)
3.5.1: Linear amides / Amidohydrolases	Asparaginase Glutaminase Urease Biotinidase Aminoacylase ACY1 Aspartoacylase(ACY2) ACY3 Ceramidase Aspartylglucosaminidase Fatty acid amide hydrolase Histone deacetylase Sirtuin
3.5.2: Cyclic amides/ Amidohydrolases	Barbiturase Beta-lactamase Dihydroorotase
3.5.3: Linear amidines/ Ureohydrolases	Arginase Agmatinase Protein-arginine deiminase
3.5.4: Cyclic amidines/ Aminohydrolases	Guanine deaminase Adenosine deaminase AMP deaminase Inosine monophosphate synthase DCMP deaminase GTP cyclohydrolase I Cytidine deaminase AICDA Activation-induced cytidine deaminase
3.5.5: Nitriles/ Aminohydrolases	Nitrilase
3.5.99: Other	Riboflavinase Thiaminase II

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)