Reaction: geranylgeranyl diphosphate + protein-cysteine = S-geranylgeranyl-protein + diphosphate
Other name(s): GGTase-I; GGTaseI
Systematic name: geranylgeranyl-diphosphate:protein-cysteine geranyltransferase
Comments: This enzyme, along with protein farnesyltransferase (EC 22.214.171.124) and protein geranylgeranyltransferase type II (EC 126.96.36.199), constitutes the protein prenyltransferase family of enzymes. Catalyses the formation of a thioether linkage between the C-1 atom of the geranylgeranyl group and a cysteine residue fourth from the C-terminus of the protein. These protein acceptors have the C-terminal sequence CA1A2X, where the terminal residue, X, is preferably leucine; serine, methionine, alanine or glutamine makes the protein a substrate for EC 188.8.131.52. The enzymes are relaxed in specificity for A1, but cannot act if A2 is aromatic. Known targets of this enzyme include most γ-subunits of heterotrimeric G proteins and Ras-related GTPases such as members of the Ras and Rac/Rho families. A zinc metalloenzyme. The Zn2+ is required for peptide, but not for isoprenoid, substrate binding.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 135371-29-8 (same as EC 184.108.40.206)
1. Casey, P.J. and Seabra, M.C. Protein prenyltransferases. J. Biol. Chem. 271 (1996) 5289-5292. [PMID: 8621375]
2. Zhang, F.L. and Casey, P.J. Influence of metal ions on substrate binding and catalytic activity of mammalian protein geranylgeranyltransferase type-I. Biochem. J. 320 (1996) 925-932. [PMID: 9003382]
3. Gibbs, R.A. Prenyl transfer and the enzymes of terpenoid and steroid biosynthesis. In: Sinnott, M. (Ed.), Comprehensive Biological Catalysis. A Mechanistic Reference., vol. 1, Academic Press, San Diego, 1998, pp. 31-118.