Reaction: (2E,6E)-farnesyl diphosphate + 4 isopentenyl diphosphate = 4 diphosphate + all-trans-heptaprenyl diphosphate
For diagram of reaction, click here
Other name(s): all-trans-heptaprenyl-diphosphate synthase; heptaprenyl pyrophosphate synthase; heptaprenyl pyrophosphate synthetase; HepPP synthase; HepPS; heptaprenylpyrophosphate synthetase
Systematic name: (2E,6E)-farnesyl-diphosphate:isopentenyl-diphosphate farnesyltranstransferase (adding 4 isopentenyl units)
Comments: This enzyme catalyses the condensation reactions resulting in the formation of all-trans-heptaprenyl diphosphate, the isoprenoid side chain of ubiquinone-7 and menaquinone-7. The enzyme adds four isopentenyl diphosphate molecules sequentially to farnesyl diphosphate with trans stereochemistry.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 74506-59-5
References:
1. Takahashi, I., Ogura, K. and Seto, S. Heptaprenyl pyrophosphate synthetase from Bacillus subtilis. J. Biol. Chem. 255 (1980) 4539-4543. [PMID: 6768722]
2. Zhang, Y.W., Koyama, T., Marecak, D.M., Prestwich, G.D., Maki, Y. and Ogura, K. Two subunits of heptaprenyl diphosphate synthase of Bacillus subtilis form a catalytically active complex. Biochemistry 37 (1998) 13411-13420. [PMID: 9748348]
3. Zhang, Y.W., Li, X.Y., Sugawara, H. and Koyama, T. Site-directed mutagenesis of the conserved residues in component I of Bacillus subtilis heptaprenyl diphosphate synthase. Biochemistry 38 (1999) 14638-14643. [PMID: 10545188]
4. Suzuki, T., Zhang, Y.W., Koyama, T., Sasaki, D.Y. and Kurihara, K. Direct observation of substrate-enzyme complexation by surface forces measurement. J. Am. Chem. Soc. 128 (2006) 15209-15214. [PMID: 17117872]