EC	2.5.1.83
Accepted name:	hexaprenyl diphosphate synthase [(2E,6E)-farnesyl-diphosphate specific]
Reaction:	(2E,6E)-farnesyl diphosphate + 3 (3-methylbut-3-en-1-yl diphosphate) = 3 diphosphate + all-trans-hexaprenyl diphosphate
Other name(s):	HexPS (ambiguous); hexaprenyl pyrophosphate synthetase (ambiguous); hexaprenyl diphosphate synthase (ambiguous); (2E,6E)-farnesyl-diphosphate:isopentenyl-diphosphate farnesyltranstransferase (adding 3 isopentenyl units)
Systematic name:	(2E,6E)-farnesyl-diphosphate:3-methylbut-3-en-1-yl-diphosphate farnesyltranstransferase (adding 3 units of 3-methylbut-3-en-1-yl)
Comments:	The enzyme prefers farnesyl diphosphate to geranylgeranyl diphosphate as an allylic substrate and does not show activity for geranyl diphosphate and prenyl diphosphate [1].
References:	1.  Fujii, H., Koyama, T. and Ogura, K. Hexaprenyl pyrophosphate synthetase from Micrococcus luteus B-P 26. Separation of two essential components. J. Biol. Chem. 257 (1982) 14610–14612. [PMID: 7174655] 2.  Shimizu, N., Koyama, T. and Ogura, K. Molecular cloning, expression, and characterization of the genes encoding the two essential protein components of Micrococcus luteus B-P 26 hexaprenyl diphosphate synthase. J. Bacteriol. 180 (1998) 1578–1581. [PMID: 9515931] 3.  Nagaki, M., Kimura, K., Kimura, H., Maki, Y., Goto, E., Nishino, T. and Koyama, T. Artificial substrates of medium-chain elongating enzymes, hexaprenyl- and heptaprenyl diphosphate synthases. Bioorg. Med. Chem. Lett. 11 (2001) 2157–2159. [PMID: 11514159]
[EC 2.5.1.83 created 1984 as EC 2.5.1.33, part transferred 2010 to EC 2.5.1.83]