Hexaprenyl diphosphate synthase (geranylgeranyl-diphosphate specific) explained

Hexaprenyl diphosphate synthase (geranylgeranyl-diphosphate specific)
Ec Number:	2.5.1.82

Hexaprenyl diphosphate synthase (geranylgeranyl-diphosphate specific) (HexPS, (all-E) hexaprenyl diphosphate synthase, (all-trans) hexaprenyl diphosphate synthase, hexaprenyl pyrophosphate synthase, HexPPs, hexaprenyl diphosphate synthase) is an enzyme with systematic name geranylgeranyl-diphosphate:isopentenyl-diphosphate transferase (adding 2 isopentenyl units).^{[1] [2] [3]} This enzyme catalyses the following chemical reaction

\rightleftharpoons 2 diphosphate + all-trans-hexaprenyl diphosphate

The enzyme prefers geranylgeranyl diphosphate to farnesyl diphosphate as an allylic substrate.

Notes and References

1. Hemmi H, Ikejiri S, Yamashita S, Nishino T . Novel medium-chain prenyl diphosphate synthase from the thermoacidophilic archaeon Sulfolobus solfataricus . Journal of Bacteriology . 184 . 3 . 615–20 . February 2002 . 11790729 . 139513 . 10.1128/JB.184.3.615-620.2002 .
2. Hemmi H, Noike M, Nakayama T, Nishino T . Change of product specificity of hexaprenyl diphosphate synthase from Sulfolobus solfataricus by introducing mimetic mutations . Biochemical and Biophysical Research Communications . 297 . 5 . 1096–101 . October 2002 . 12372398 . 10.1016/S0006-291X(02)02348-3 .
3. Sun HY, Ko TP, Kuo CJ, Guo RT, Chou CC, Liang PH, Wang AH . Homodimeric hexaprenyl pyrophosphate synthase from the thermoacidophilic crenarchaeon Sulfolobus solfataricus displays asymmetric subunit structures . Journal of Bacteriology . 187 . 23 . 8137–48 . December 2005 . 16291686 . 1291270 . 10.1128/JB.187.23.8137-8148.2005 .