EC - Heterotrimeric G-protein GTPase

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IntEnz Enzyme Nomenclature


Accepted name:
heterotrimeric G-protein GTPase
Systematic name:
GTP phosphohydrolase (signalling)



This group comprises GTP-hydrolysing systems, where GTP and GDP alternate in binding. This group includes stimulatory and inhibitory G-proteins such as Gs, Gi, Go and Golf, targetting adenylate cyclase and/or K+ and Ca2+ channels; Gq stimulating phospholipase C; transducin activating cGMP phosphodiesterase; gustducin activating cAMP phosphodiesterase. Golf is instrumental in odour perception, transducin in vision and gustducin in taste recognition. At least 16 different α subunits (39-52 kDa), 5 β subunits (36 kDa) and 12 γ subunits (6-9 kDa) are known.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC01002
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003925


  1. Neer, E.J.
    Heterotrimeric G proteins: organizers of transmembrane signals.
    Cell 80 : 249-259 (1995). [PMID: 7834744]
  2. Sprang, S.R.
    G protein mechanisms: insights from structural analysis.
    Annu. Rev. Biochem. 66 : 639-678 (1997). [PMID: 9242920]
  3. Bondarenko, V.A., Deasi, M., Dua, S., Yamazaki, M., Amin, R.H., Yousif, K.K., Kinumi, T., Ohashi, M., Komori, N., Matsumoto, H., Jackson, K.W., Hayashi, F., Usukura, J., Lipikin, V.M. and Yamazaki, A.
    Residues within the polycationic region of cGMP phosphodiesterase γ subunit crucial for the interaction with transducin α subunit. Identification by endogenous ADP-ribosylation and site-directed mutagenesis.
    J. Biol. Chem. 272 : 15856-15864 (1997). [PMID: 9188484]
  4. Ming, D., Ruiz-Avila, L. and Margolskee, R.F.
    Characterization and solubilization of bitter-responsive receptors that couple to gustducin.
    Proc. Natl. Acad. Sci. USA 95 : 8933-8938 (1998). [PMID: 9671782]

[EC created 2000 as EC, transferred 2003 to EC]