Available structures
PDBOrtholog search: PDBe RCSB
AliasesGDA, guanine deaminase, CYPIN, GUANASE, NEDASIN, Guanine deaminase, GAH
External IDsOMIM: 139260; MGI: 95678; HomoloGene: 3171; GeneCards: GDA; OMA:GDA - orthologs
RefSeq (mRNA)


RefSeq (protein)


Location (UCSC)Chr 9: 72.11 – 72.26 MbChr 19: 21.37 – 21.45 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Guanine deaminase also known as cypin, guanase, guanine aminase, GAH, and guanine aminohydrolase is an aminohydrolase enzyme which converts guanine to xanthine.[5][6][7] Cypin is a major cytosolic protein that interacts with PSD-95. It promotes localized microtubule assembly in neuronal dendrites.[8]

Xanthine synthesis from guanine


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000119125Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000058624Ensembl, 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 (Oct 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): 294–7. Bibcode:1944PNAS...30..294H. doi:10.1073/pnas.30.10.294. PMC 1078714. PMID 16578130.
  6. ^ Kalckar HM (1947). "Differential spectrophotometry of purine compounds by means of specific enzymes; studies of the enzymes of purine metabolism". J. Biol. Chem. 167 (2): 461–75. doi:10.1016/S0021-9258(17)30999-7. PMID 20285041.
  7. ^ Rabinowitz JC, Barker HA (Jan 1956). "Purine fermentation by Clostridium cylindrosporum. II. Purine transformations". The Journal of Biological Chemistry. 218 (1): 161–73. doi:10.1016/S0021-9258(18)65881-8. PMID 13278325.
  8. ^ Firestein BL, Firestein BL, Brenman JE, Aoki C, Sanchez-Perez AM, El-Husseini AE, Bredt DS (1999). "Cypin: a cytosolic regulator of PSD-95 postsynaptic targeting". Neuron. 24 (3): 659–72. doi:10.1016/S0896-6273(00)81120-4. PMID 10595517.